diff --git a/app/Features/Spaces.php b/app/Features/Spaces.php
new file mode 100644
index 00000000..23322b0c
--- /dev/null
+++ b/app/Features/Spaces.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace App\Features;
+
+use App\Models\User;
+
+/**
+ * Gates the visible spaces UI (the switcher and space management). The
+ * space-scoping of data is always on and safe; this flag only controls whether
+ * a user can see and manage more than their invisible personal space. Defaults
+ * to admins for internal dogfooding; flipped to the Business plan at launch.
+ *
+ * @api
+ */
+class Spaces
+{
+    /**
+     * Resolve the feature's initial value.
+     */
+    public function resolve(?User $user): bool
+    {
+        return $user?->isAdmin() ?? false;
+    }
+}
diff --git a/app/Http/Controllers/AccountController.php b/app/Http/Controllers/AccountController.php
index 9e42d3f1..ab6b6a4e 100644
--- a/app/Http/Controllers/AccountController.php
+++ b/app/Http/Controllers/AccountController.php
@@ -29,8 +29,7 @@ class AccountController extends Controller
     {
         $user = $request->user();
 
-        $accounts = Account::query()
-            ->where('user_id', $user->id)
+        $accounts = $user->activeSpace()->accounts()
             ->with(['bank', 'realEstateDetail:id,account_id,linked_loan_account_id'])
             ->orderBy('position')
             ->orderBy('name')
@@ -50,10 +49,11 @@ class AccountController extends Controller
     {
         // ponytail: one update per account; fine for the handful of accounts a
         // user has. Switch to a single CASE update if that ever grows large.
+        $space = $request->user()->activeSpace();
+
         foreach (array_values($request->validated('ids')) as $position => $id) {
-            Account::query()
+            $space->accounts()
                 ->whereKey($id)
-                ->where('user_id', $request->user()->id)
                 ->update(['position' => $position]);
         }
 
@@ -105,7 +105,7 @@ class AccountController extends Controller
             }
 
             // Provide available loan accounts for linking
-            $data['available_loan_accounts'] = $request->user()
+            $data['available_loan_accounts'] = $request->user()->activeSpace()
                 ->accounts()
                 ->where('type', AccountType::Loan->value)
                 ->with('bank')
diff --git a/app/Http/Controllers/Api/AccountController.php b/app/Http/Controllers/Api/AccountController.php
index 9bcd7950..dded9ff6 100644
--- a/app/Http/Controllers/Api/AccountController.php
+++ b/app/Http/Controllers/Api/AccountController.php
@@ -20,7 +20,9 @@ class AccountController extends Controller
     {
         // The decryption-migration flow needs bank_id, which Account hides by
         // default; opt it back in explicitly here.
-        $accounts = $request->user()
+        $space = $request->user()->activeSpace();
+
+        $accounts = $space
             ->accounts()
             ->get()
             ->makeVisible('bank_id');
diff --git a/app/Http/Controllers/Api/CashflowAnalyticsController.php b/app/Http/Controllers/Api/CashflowAnalyticsController.php
index d6543ab0..4c69555e 100644
--- a/app/Http/Controllers/Api/CashflowAnalyticsController.php
+++ b/app/Http/Controllers/Api/CashflowAnalyticsController.php
@@ -39,9 +39,10 @@ class CashflowAnalyticsController extends Controller
         $period = PeriodComparator::fromRequest($validated);
         $previousPeriod = $period->previous();
         $user = $request->user();
+        $space = $user->activeSpace();
 
         return $this->cashflowJson(
-            $this->calculateCashflowSummaries($user->id, $user->currency_code, $period, $previousPeriod)
+            $this->calculateCashflowSummaries($space->id, $user->currency_code, $period, $previousPeriod)
         );
     }
 
@@ -56,12 +57,13 @@ class CashflowAnalyticsController extends Controller
         $from = Carbon::parse($validated['from']);
         $to = Carbon::parse($validated['to']);
         $user = $request->user();
+        $space = $user->activeSpace();
         $drillParentId = $validated['parent'] ?? null;
 
         // Split by sign, not by category type: a single category can appear on
         // both sides when it has both incoming and outgoing transactions.
-        $incomeCategories = $this->getSankeyBreakdown($user->id, $user->currency_code, $from, $to, '>', $drillParentId);
-        $expenseCategories = $this->getSankeyBreakdown($user->id, $user->currency_code, $from, $to, '<', $drillParentId);
+        $incomeCategories = $this->getSankeyBreakdown($space->id, $user->currency_code, $from, $to, '>', $drillParentId);
+        $expenseCategories = $this->getSankeyBreakdown($space->id, $user->currency_code, $from, $to, '<', $drillParentId);
 
         $totalIncome = $incomeCategories->sum('amount');
         $totalExpense = $expenseCategories->sum('amount');
@@ -83,6 +85,7 @@ class CashflowAnalyticsController extends Controller
         ]);
 
         $user = $request->user();
+        $space = $user->activeSpace();
 
         if (isset($validated['from'], $validated['to'])) {
             $start = Carbon::parse($validated['from'])->startOfMonth();
@@ -104,7 +107,7 @@ class CashflowAnalyticsController extends Controller
             $start = $earliestStart;
         }
 
-        $monthlyTotals = $this->getMonthlyTrendTotals($user->id, $user->currency_code, $start, $end);
+        $monthlyTotals = $this->getMonthlyTrendTotals($space->id, $user->currency_code, $start, $end);
 
         $data = [];
         $current = $start->copy();
@@ -142,12 +145,13 @@ class CashflowAnalyticsController extends Controller
         $period = PeriodComparator::fromRequest($validated);
         $previousPeriod = $period->previous();
         $user = $request->user();
+        $space = $user->activeSpace();
         $drillParentId = $validated['parent'] ?? null;
 
         $categoryType = $validated['type'] === 'income' ? CategoryType::Income : CategoryType::Expense;
 
-        $current = $this->getCategoryBreakdown($user->id, $user->currency_code, $period->from, $period->to, $categoryType, $drillParentId);
-        $previous = $this->getCategoryBreakdown($user->id, $user->currency_code, $previousPeriod->from, $previousPeriod->to, $categoryType, $drillParentId);
+        $current = $this->getCategoryBreakdown($space->id, $user->currency_code, $period->from, $period->to, $categoryType, $drillParentId);
+        $previous = $this->getCategoryBreakdown($space->id, $user->currency_code, $previousPeriod->from, $previousPeriod->to, $categoryType, $drillParentId);
 
         $currentTotal = $current->sum('amount');
         $previousTotal = $previous->sum('amount');
@@ -181,10 +185,10 @@ class CashflowAnalyticsController extends Controller
             ->header('Cache-Control', 'no-store, private');
     }
 
-    private function calculateCashflowSummaries(string $userId, string $userCurrency, PeriodComparator $period, PeriodComparator $previousPeriod): array
+    private function calculateCashflowSummaries(string $spaceId, string $userCurrency, PeriodComparator $period, PeriodComparator $previousPeriod): array
     {
         $transactions = Transaction::query()
-            ->where('transactions.user_id', $userId)
+            ->where('transactions.space_id', $spaceId)
             ->whereBetween('transactions.transaction_date', [$previousPeriod->from, $period->to])
             ->with(['account', 'category'])
             ->get();
@@ -238,12 +242,12 @@ class CashflowAnalyticsController extends Controller
             ->sum(fn (Transaction $transaction): int => $this->convertTransactionAmount($transaction, $userCurrency)));
     }
 
-    private function getSankeyBreakdown(string $userId, string $userCurrency, Carbon $from, Carbon $to, string $operator, ?string $drillParentId = null): Collection
+    private function getSankeyBreakdown(string $spaceId, string $userCurrency, Carbon $from, Carbon $to, string $operator, ?string $drillParentId = null): Collection
     {
         $isIncome = $operator === '>';
         $type = $isIncome ? CategoryType::Income : CategoryType::Expense;
         $transactions = Transaction::query()
-            ->where('transactions.user_id', $userId)
+            ->where('transactions.space_id', $spaceId)
             ->whereBetween('transactions.transaction_date', [$from, $to])
             ->with(['account', 'category'])
             ->get();
@@ -305,7 +309,7 @@ class CashflowAnalyticsController extends Controller
 
         $categorized = collect($this->tree->rollUp(
             $regularCategories->concat($transferCategories)->values()->all(),
-            $userId,
+            $spaceId,
             $drillParentId,
         ));
 
@@ -335,10 +339,10 @@ class CashflowAnalyticsController extends Controller
         return $categorized;
     }
 
-    private function getMonthlyTrendTotals(string $userId, string $userCurrency, Carbon $from, Carbon $to): Collection
+    private function getMonthlyTrendTotals(string $spaceId, string $userCurrency, Carbon $from, Carbon $to): Collection
     {
         $transactions = Transaction::query()
-            ->where('transactions.user_id', $userId)
+            ->where('transactions.space_id', $spaceId)
             ->whereBetween('transactions.transaction_date', [$from, $to])
             ->with(['account', 'category'])
             ->get();
@@ -393,10 +397,10 @@ class CashflowAnalyticsController extends Controller
             });
     }
 
-    private function getCategoryBreakdown(string $userId, string $userCurrency, Carbon $from, Carbon $to, CategoryType $type, ?string $drillParentId = null): Collection
+    private function getCategoryBreakdown(string $spaceId, string $userCurrency, Carbon $from, Carbon $to, CategoryType $type, ?string $drillParentId = null): Collection
     {
         $transactions = Transaction::query()
-            ->where('transactions.user_id', $userId)
+            ->where('transactions.space_id', $spaceId)
             ->whereBetween('transactions.transaction_date', [$from, $to])
             ->with(['account', 'category'])
             ->get();
@@ -423,7 +427,7 @@ class CashflowAnalyticsController extends Controller
                 'amount' => $item['amount'],
             ]);
 
-        $categorized = collect($this->tree->rollUp($categorized->values()->all(), $userId, $drillParentId));
+        $categorized = collect($this->tree->rollUp($categorized->values()->all(), $spaceId, $drillParentId));
 
         $uncategorized = $transactions
             ->filter(function (Transaction $transaction) use ($type): bool {
diff --git a/app/Http/Controllers/Api/CategoryMonthlyBreakdownController.php b/app/Http/Controllers/Api/CategoryMonthlyBreakdownController.php
index 7e005a83..27d57a83 100644
--- a/app/Http/Controllers/Api/CategoryMonthlyBreakdownController.php
+++ b/app/Http/Controllers/Api/CategoryMonthlyBreakdownController.php
@@ -6,7 +6,6 @@ use App\Enums\CategoryType;
 use App\Http\Controllers\Api\Concerns\ConvertsTransactionCurrency;
 use App\Http\Controllers\Controller;
 use App\Models\Category;
-use App\Models\Transaction;
 use App\Services\ExchangeRateService;
 use Carbon\Carbon;
 use Illuminate\Http\JsonResponse;
@@ -35,19 +34,18 @@ class CategoryMonthlyBreakdownController extends Controller
     public function __invoke(Request $request, Category $category): JsonResponse
     {
         $user = $request->user();
+        $space = $user->activeSpace();
 
-        abort_unless($category->user_id === $user->id, 403);
+        abort_unless($category->space_id === $space->id, 403);
 
         $currency = $user->currency_code;
         $start = Carbon::now()->startOfMonth()->subMonths(self::MONTHS - 1);
 
-        $parentMap = Category::query()
-            ->where('user_id', $user->id)
+        $parentMap = $space->categories()
             ->pluck('parent_id', 'id')
             ->all();
 
-        $children = Category::query()
-            ->where('user_id', $user->id)
+        $children = $space->categories()
             ->where('parent_id', $category->id)
             ->orderBy('name')
             ->get()
@@ -58,8 +56,7 @@ class CategoryMonthlyBreakdownController extends Controller
             fn (string $id): bool => $this->belongsToSubtree($id, $category->id, $parentMap),
         ));
 
-        $transactions = Transaction::query()
-            ->where('user_id', $user->id)
+        $transactions = $space->transactions()
             ->whereIn('category_id', $subtreeIds)
             ->where('transaction_date', '>=', $start->toDateString())
             ->with('account')
diff --git a/app/Http/Controllers/Api/DashboardAnalyticsController.php b/app/Http/Controllers/Api/DashboardAnalyticsController.php
index b80a9772..bfec5391 100644
--- a/app/Http/Controllers/Api/DashboardAnalyticsController.php
+++ b/app/Http/Controllers/Api/DashboardAnalyticsController.php
@@ -38,9 +38,8 @@ class DashboardAnalyticsController extends Controller
 
         $userCurrency = $request->user()->currency_code;
 
-        $accounts = Account::query()
-            ->where('user_id', $request->user()->id)
-            ->get();
+        $space = $request->user()->activeSpace();
+        $accounts = $space->accounts()->get();
 
         // Load every account's balance history for the compared range in a
         // fixed number of queries instead of one balance lookup per account.
@@ -101,8 +100,8 @@ class DashboardAnalyticsController extends Controller
 
         $userCurrency = $request->user()->currency_code;
 
-        $accounts = Account::query()
-            ->where('user_id', $request->user()->id)
+        $space = $request->user()->activeSpace();
+        $accounts = $space->accounts()
             ->with(['bank:id,name,logo'])
             ->get();
 
@@ -113,7 +112,7 @@ class DashboardAnalyticsController extends Controller
 
     public function accountBalanceEvolution(Request $request, Account $account)
     {
-        if ($account->user_id !== $request->user()->id) {
+        if ($account->space_id !== $request->user()->activeSpace()->id) {
             abort(403);
         }
 
@@ -319,7 +318,7 @@ class DashboardAnalyticsController extends Controller
 
     public function accountDailyBalanceEvolution(Request $request, Account $account)
     {
-        if ($account->user_id !== $request->user()->id) {
+        if ($account->space_id !== $request->user()->activeSpace()->id) {
             abort(403);
         }
 
@@ -426,8 +425,8 @@ class DashboardAnalyticsController extends Controller
 
         $userCurrency = $request->user()->currency_code;
 
-        $accounts = Account::query()
-            ->where('user_id', $request->user()->id)
+        $space = $request->user()->activeSpace();
+        $accounts = $space->accounts()
             ->with(['bank:id,name,logo'])
             ->get();
 
@@ -448,8 +447,9 @@ class DashboardAnalyticsController extends Controller
         $previousPeriod = $period->previous();
         $drillParentId = $validated['parent'] ?? null;
 
-        $currentSpending = $this->categorySpendingService->forPeriod($request->user()->id, $period->from, $period->to, $drillParentId);
-        $previousSpending = $this->categorySpendingService->forPeriod($request->user()->id, $previousPeriod->from, $previousPeriod->to, $drillParentId);
+        $space = $request->user()->activeSpace();
+        $currentSpending = $this->categorySpendingService->forPeriod($space->id, $period->from, $period->to, $drillParentId);
+        $previousSpending = $this->categorySpendingService->forPeriod($space->id, $previousPeriod->from, $previousPeriod->to, $drillParentId);
 
         $totalAmount = $currentSpending->sum('amount');
 
@@ -505,8 +505,10 @@ class DashboardAnalyticsController extends Controller
 
     private function calculateSpending(Carbon $from, Carbon $to): int
     {
+        $space = request()->user()->activeSpace();
+
         $spending = Transaction::query()
-            ->where('transactions.user_id', request()->user()->id)
+            ->where('transactions.space_id', $space->id)
             ->whereBetween('transactions.transaction_date', [$from, $to])
             ->join('categories', function ($join) {
                 $join->on('transactions.category_id', '=', 'categories.id')
@@ -520,8 +522,10 @@ class DashboardAnalyticsController extends Controller
 
     private function calculateCashFlow(Carbon $from, Carbon $to): array
     {
+        $space = request()->user()->activeSpace();
+
         $income = Transaction::query()
-            ->where('transactions.user_id', request()->user()->id)
+            ->where('transactions.space_id', $space->id)
             ->whereBetween('transactions.transaction_date', [$from, $to])
             ->join('categories', function ($join) {
                 $join->on('transactions.category_id', '=', 'categories.id')
@@ -531,7 +535,7 @@ class DashboardAnalyticsController extends Controller
             ->sum('transactions.amount');
 
         $expense = Transaction::query()
-            ->where('transactions.user_id', request()->user()->id)
+            ->where('transactions.space_id', $space->id)
             ->whereBetween('transactions.transaction_date', [$from, $to])
             ->join('categories', function ($join) {
                 $join->on('transactions.category_id', '=', 'categories.id')
diff --git a/app/Http/Controllers/Api/ImportDataController.php b/app/Http/Controllers/Api/ImportDataController.php
index bf4f582b..8333a642 100644
--- a/app/Http/Controllers/Api/ImportDataController.php
+++ b/app/Http/Controllers/Api/ImportDataController.php
@@ -13,19 +13,20 @@ class ImportDataController extends Controller
     public function index(): JsonResponse
     {
         $user = auth()->user();
+        $space = $user->activeSpace();
 
         return response()->json([
-            'accounts' => $user->accounts()
+            'accounts' => $space->accounts()
                 ->with('bank')
                 ->orderBy('name')
                 ->get(),
-            'categories' => $user->categories()
+            'categories' => $space->categories()
                 ->forDisplay()
                 ->get(),
             'banks' => $user->banks()
                 ->orderBy('name')
                 ->get(),
-            'automationRules' => $user->automationRules()
+            'automationRules' => $space->automationRules()
                 ->with(['category', 'labels'])
                 ->orderBy('priority')
                 ->get(),
diff --git a/app/Http/Controllers/Api/SavedFilterController.php b/app/Http/Controllers/Api/SavedFilterController.php
index 56575109..a1eef0ae 100644
--- a/app/Http/Controllers/Api/SavedFilterController.php
+++ b/app/Http/Controllers/Api/SavedFilterController.php
@@ -15,8 +15,8 @@ class SavedFilterController extends Controller
 {
     public function index(Request $request): JsonResponse
     {
-        $savedFilters = SavedFilter::query()
-            ->where('user_id', $request->user()->id)
+        $savedFilters = $request->user()->activeSpace()
+            ->savedFilters()
             ->orderBy('name')
             ->get();
 
@@ -38,7 +38,7 @@ class SavedFilterController extends Controller
 
     public function update(UpdateSavedFilterRequest $request, SavedFilter $savedFilter): JsonResponse
     {
-        abort_unless($savedFilter->user_id === $request->user()->id, 403);
+        abort_unless($savedFilter->space_id === $request->user()->activeSpace()->id, 403);
 
         $savedFilter->update(['filters' => $request->validated('filters')]);
 
@@ -49,7 +49,7 @@ class SavedFilterController extends Controller
 
     public function destroy(Request $request, SavedFilter $savedFilter): JsonResponse
     {
-        abort_unless($savedFilter->user_id === $request->user()->id, 403);
+        abort_unless($savedFilter->space_id === $request->user()->activeSpace()->id, 403);
 
         $savedFilter->delete();
 
@@ -58,7 +58,7 @@ class SavedFilterController extends Controller
 
     public function updateAnalysisDays(Request $request, SavedFilter $savedFilter): JsonResponse
     {
-        abort_unless($savedFilter->user_id === $request->user()->id, 403);
+        abort_unless($savedFilter->space_id === $request->user()->activeSpace()->id, 403);
 
         $validated = $request->validate([
             'analysis_days' => ['nullable', 'integer', 'min:1', 'max:36500'],
@@ -73,7 +73,7 @@ class SavedFilterController extends Controller
 
     public function updateAnalysisMode(Request $request, SavedFilter $savedFilter): JsonResponse
     {
-        abort_unless($savedFilter->user_id === $request->user()->id, 403);
+        abort_unless($savedFilter->space_id === $request->user()->activeSpace()->id, 403);
 
         $validated = $request->validate([
             'analysis_mode' => ['nullable', Rule::enum(AnalysisMode::class)],
diff --git a/app/Http/Controllers/Api/TransactionAnalysisController.php b/app/Http/Controllers/Api/TransactionAnalysisController.php
index ed325060..295e0efb 100644
--- a/app/Http/Controllers/Api/TransactionAnalysisController.php
+++ b/app/Http/Controllers/Api/TransactionAnalysisController.php
@@ -37,6 +37,7 @@ class TransactionAnalysisController extends Controller
     public function summary(IndexTransactionRequest $request): JsonResponse
     {
         $user = $request->user();
+        $space = $user->activeSpace();
 
         $validated = $request->validated();
         $currency = $user->currency_code;
@@ -54,15 +55,14 @@ class TransactionAnalysisController extends Controller
             'search' => $validated['search'] ?? null,
         ], fn ($value) => $value !== null);
 
-        $transactions = Transaction::query()
-            ->where('user_id', $user->id)
+        $transactions = $space->transactions()
             ->with(['account.bank', 'category', 'labels'])
             ->applyFilters($filters)
             ->get();
 
         $this->preloadExchangeRates($transactions, $currency);
 
-        $byCategory = $this->categoryBreakdown($transactions, $currency, $user->id);
+        $byCategory = $this->categoryBreakdown($transactions, $currency, $space->id);
         $byTag = $this->tagBreakdown($transactions, $currency);
         $byPayee = $this->payeeBreakdown($transactions, $currency);
         $byAccount = $this->accountBreakdown($transactions, $currency);
@@ -124,7 +124,7 @@ class TransactionAnalysisController extends Controller
      * that carry spending nested beneath each parent so the split is visible
      * instead of folded into the parent total.
      */
-    private function categoryBreakdown(Collection $transactions, string $currency, string $userId): Collection
+    private function categoryBreakdown(Collection $transactions, string $currency, string $spaceId): Collection
     {
         $expenses = $transactions->filter(
             fn (Transaction $transaction): bool => $transaction->isExpenseSide(),
@@ -154,7 +154,7 @@ class TransactionAnalysisController extends Controller
                 'icon' => $child['category']->icon,
                 'amount' => $child['amount'],
             ], $node['children']),
-        ], $this->tree->spendingBreakdown($grouped, $userId));
+        ], $this->tree->spendingBreakdown($grouped, $spaceId));
 
         $uncategorized = -$expenses
             ->filter(fn (Transaction $transaction): bool => $transaction->category_id === null)
diff --git a/app/Http/Controllers/Api/TransactionController.php b/app/Http/Controllers/Api/TransactionController.php
index 0c1723ae..f9bb9d15 100644
--- a/app/Http/Controllers/Api/TransactionController.php
+++ b/app/Http/Controllers/Api/TransactionController.php
@@ -16,7 +16,9 @@ class TransactionController extends Controller
      */
     public function index(Request $request): JsonResponse
     {
-        $query = $request->user()
+        $space = $request->user()->activeSpace();
+
+        $query = $space
             ->transactions()
             ->with('labels');
 
@@ -48,7 +50,8 @@ class TransactionController extends Controller
     public function checkDuplicates(CheckDuplicateTransactionsRequest $request): JsonResponse
     {
         $validated = $request->validated();
-        $account = $request->user()->accounts()->findOrFail($validated['account_id']);
+        $space = $request->user()->activeSpace();
+        $account = $space->accounts()->findOrFail($validated['account_id']);
         $incoming = $validated['transactions'];
 
         $dates = array_map(fn (array $t): string => substr($t['transaction_date'], 0, 10), $incoming);
@@ -103,7 +106,9 @@ class TransactionController extends Controller
 
         $transactionIds = collect($validated['transactions'])->pluck('id');
 
-        $userTransactionIds = $request->user()
+        $space = $request->user()->activeSpace();
+
+        $userTransactionIds = $space
             ->transactions()
             ->whereIn('id', $transactionIds)
             ->pluck('id');
diff --git a/app/Http/Controllers/BudgetController.php b/app/Http/Controllers/BudgetController.php
index c42457ba..2a2f7dcd 100644
--- a/app/Http/Controllers/BudgetController.php
+++ b/app/Http/Controllers/BudgetController.php
@@ -5,11 +5,8 @@ namespace App\Http\Controllers;
 use App\Http\Requests\StoreBudgetRequest;
 use App\Http\Requests\UpdateBudgetRequest;
 use App\Jobs\AssignHistoricalTransactionsToBudget;
-use App\Models\Account;
 use App\Models\Bank;
 use App\Models\Budget;
-use App\Models\Category;
-use App\Models\Label;
 use App\Services\BudgetPeriodService;
 use Illuminate\Foundation\Auth\Access\AuthorizesRequests;
 use Illuminate\Http\RedirectResponse;
@@ -27,7 +24,7 @@ class BudgetController extends Controller
     public function index(Request $request): Response
     {
         $user = $request->user();
-        $budgets = $user
+        $budgets = $user->activeSpace()
             ->budgets()
             ->with(['categories', 'labels', 'periods' => function ($query) {
                 $query->where('start_date', '<=', today())
@@ -83,13 +80,13 @@ class BudgetController extends Controller
 
         $budget->load(['categories', 'labels']);
 
-        $categories = Category::query()
-            ->where('user_id', $user->id)
+        $space = $user->activeSpace();
+
+        $categories = $space->categories()
             ->forDisplay()
             ->get();
 
-        $accounts = Account::query()
-            ->where('user_id', $user->id)
+        $accounts = $space->accounts()
             ->with('bank')
             ->orderBy('name')
             ->get();
@@ -99,8 +96,7 @@ class BudgetController extends Controller
             ->orderBy('name')
             ->get();
 
-        $labels = Label::query()
-            ->where('user_id', $user->id)
+        $labels = $space->labels()
             ->orderBy('name')
             ->get();
 
diff --git a/app/Http/Controllers/CashflowController.php b/app/Http/Controllers/CashflowController.php
index 67dd0e28..9fce3cc8 100644
--- a/app/Http/Controllers/CashflowController.php
+++ b/app/Http/Controllers/CashflowController.php
@@ -2,9 +2,7 @@
 
 namespace App\Http\Controllers;
 
-use App\Models\Account;
 use App\Models\Bank;
-use App\Models\Category;
 use Illuminate\Http\Request;
 use Inertia\Inertia;
 use Inertia\Response;
@@ -14,14 +12,13 @@ class CashflowController extends Controller
     public function __invoke(Request $request): Response
     {
         $user = $request->user();
+        $space = $user->activeSpace();
 
-        $categories = Category::query()
-            ->where('user_id', $user->id)
+        $categories = $space->categories()
             ->forDisplay()
             ->get();
 
-        $accounts = Account::query()
-            ->where('user_id', $user->id)
+        $accounts = $space->accounts()
             ->with('bank')
             ->orderBy('name')
             ->get();
diff --git a/app/Http/Controllers/DashboardController.php b/app/Http/Controllers/DashboardController.php
index f85ba628..b3771399 100644
--- a/app/Http/Controllers/DashboardController.php
+++ b/app/Http/Controllers/DashboardController.php
@@ -3,7 +3,6 @@
 namespace App\Http\Controllers;
 
 use App\Enums\CategoryType;
-use App\Models\Account;
 use App\Models\Transaction;
 use App\Services\AccountMetricsService;
 use App\Services\CashflowSummaryService;
@@ -39,8 +38,7 @@ class DashboardController extends Controller
         $start = $now->copy()->subMonths(12);
         $end = $now->copy();
 
-        $accounts = Account::query()
-            ->where('user_id', $user->id)
+        $accounts = $user->activeSpace()->accounts()
             ->with(['bank:id,name,logo', 'realEstateDetail:account_id,linked_loan_account_id'])
             ->orderBy('position')
             ->orderBy('name')
@@ -59,8 +57,9 @@ class DashboardController extends Controller
         $period = new PeriodComparator($from, $to);
         $previousPeriod = $period->previous();
 
-        $currentSpending = $this->categorySpendingService->forPeriod($user->id, $period->from, $period->to);
-        $previousSpending = $this->categorySpendingService->forPeriod($user->id, $previousPeriod->from, $previousPeriod->to);
+        $spaceId = $user->activeSpace()->id;
+        $currentSpending = $this->categorySpendingService->forPeriod($spaceId, $period->from, $period->to);
+        $previousSpending = $this->categorySpendingService->forPeriod($spaceId, $previousPeriod->from, $previousPeriod->to);
 
         $totalAmount = $currentSpending->sum('amount');
 
@@ -94,24 +93,26 @@ class DashboardController extends Controller
         $period = new PeriodComparator($from, $to);
         $previousPeriod = $period->previous();
 
+        $spaceId = $user->activeSpace()->id;
+
         return [
-            'current' => $this->calculateCashflowSummary($user->id, $period->from, $period->to),
-            'previous' => $this->calculateCashflowSummary($user->id, $previousPeriod->from, $previousPeriod->to),
+            'current' => $this->calculateCashflowSummary($spaceId, $period->from, $period->to),
+            'previous' => $this->calculateCashflowSummary($spaceId, $previousPeriod->from, $previousPeriod->to),
         ];
     }
 
-    private function calculateCashflowSummary(string $userId, Carbon $from, Carbon $to): array
+    private function calculateCashflowSummary(string $spaceId, Carbon $from, Carbon $to): array
     {
-        $income = max(0, $this->getTransactionSum($userId, $from, $to, CategoryType::Income));
-        $expense = max(0, -$this->getTransactionSum($userId, $from, $to, CategoryType::Expense));
+        $income = max(0, $this->getTransactionSum($spaceId, $from, $to, CategoryType::Income));
+        $expense = max(0, -$this->getTransactionSum($spaceId, $from, $to, CategoryType::Expense));
 
         return CashflowSummaryService::summarize($income, $expense);
     }
 
-    private function getTransactionSum(string $userId, Carbon $from, Carbon $to, CategoryType $type): int
+    private function getTransactionSum(string $spaceId, Carbon $from, Carbon $to, CategoryType $type): int
     {
         return Transaction::query()
-            ->where('transactions.user_id', $userId)
+            ->where('transactions.space_id', $spaceId)
             ->whereBetween('transactions.transaction_date', [$from, $to])
             ->where(function ($q) use ($type) {
                 $q->whereExists(function ($sub) use ($type) {
diff --git a/app/Http/Controllers/OnboardingController.php b/app/Http/Controllers/OnboardingController.php
index 7bb3a62a..93f835e5 100644
--- a/app/Http/Controllers/OnboardingController.php
+++ b/app/Http/Controllers/OnboardingController.php
@@ -5,8 +5,6 @@ namespace App\Http\Controllers;
 use App\Enums\BankingConnectionStatus;
 use App\Jobs\CategorizeOnboardingTransactionsJob;
 use App\Models\Bank;
-use App\Models\Category;
-use App\Models\Transaction;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Http\Request;
@@ -38,23 +36,22 @@ class OnboardingController extends Controller
     public function index(Request $request): Response
     {
         $user = $request->user();
+        $space = $user->activeSpace();
 
         $banks = Bank::query()
             ->availableForUser($user)
             ->orderBy('name')
             ->get();
 
-        $accounts = $user->accounts()
+        $accounts = $space->accounts()
             ->with('bank')
             ->get();
 
-        $categories = Category::query()
-            ->where('user_id', $user->id)
+        $categories = $space->categories()
             ->forDisplay()
             ->get();
 
-        $transactions = Transaction::query()
-            ->where('user_id', $user->id)
+        $transactions = $space->transactions()
             ->whereNull('category_id')
             ->with(['account.bank', 'labels'])
             ->orderBy('transaction_date', 'desc')
@@ -77,7 +74,9 @@ class OnboardingController extends Controller
 
     public function syncStatus(Request $request): JsonResponse
     {
-        $pending = $request->user()
+        $space = $request->user()->activeSpace();
+
+        $pending = $space
             ->bankingConnections()
             ->where('status', BankingConnectionStatus::Active)
             ->whereNull('last_synced_at')
diff --git a/app/Http/Controllers/Settings/AccountController.php b/app/Http/Controllers/Settings/AccountController.php
index f1fd7a7c..6a4c6d2c 100644
--- a/app/Http/Controllers/Settings/AccountController.php
+++ b/app/Http/Controllers/Settings/AccountController.php
@@ -32,8 +32,9 @@ class AccountController extends Controller
     {
         /** @var User $user */
         $user = Auth::user();
+        $space = $user->activeSpace();
 
-        $accounts = $user
+        $accounts = $space
             ->accounts()
             ->with(['bank', 'loanDetail', 'realEstateDetail'])
             ->orderBy('name')
@@ -51,6 +52,7 @@ class AccountController extends Controller
     {
         /** @var User $user */
         $user = Auth::user();
+        $space = $user->activeSpace();
         $validated = $request->validated();
         $balance = $validated['balance'] ?? null;
 
@@ -157,7 +159,7 @@ class AccountController extends Controller
             $linkedRealEstateAccountId = $validated['linked_real_estate_account_id'] ?? null;
 
             if ($linkedRealEstateAccountId !== null) {
-                $realEstateAccount = $user->accounts()
+                $realEstateAccount = $space->accounts()
                     ->whereKey($linkedRealEstateAccountId)
                     ->where('type', AccountType::RealEstate->value)
                     ->with('realEstateDetail')
diff --git a/app/Http/Controllers/Settings/AutomationRuleApplicationController.php b/app/Http/Controllers/Settings/AutomationRuleApplicationController.php
index a72ec5d0..c8ad0487 100644
--- a/app/Http/Controllers/Settings/AutomationRuleApplicationController.php
+++ b/app/Http/Controllers/Settings/AutomationRuleApplicationController.php
@@ -97,7 +97,7 @@ class AutomationRuleApplicationController extends Controller
 
         if ($total <= self::SYNC_THRESHOLD) {
             $transactions = Transaction::query()
-                ->where('user_id', $automationRule->user_id)
+                ->where('space_id', $automationRule->space_id)
                 ->whereIn('id', $matchingIds)
                 ->whereNull('description_iv')
                 ->with(['account.bank', 'category', 'labels'])
@@ -177,7 +177,7 @@ class AutomationRuleApplicationController extends Controller
         }
 
         Transaction::query()
-            ->where('user_id', $rule->user_id)
+            ->where('space_id', $rule->space_id)
             ->whereNull('description_iv')
             ->with(array_values(array_unique($eagerLoads)))
             ->orderByDesc('transaction_date')
diff --git a/app/Http/Controllers/Settings/CategoryController.php b/app/Http/Controllers/Settings/CategoryController.php
index ba072bc4..aa96248a 100644
--- a/app/Http/Controllers/Settings/CategoryController.php
+++ b/app/Http/Controllers/Settings/CategoryController.php
@@ -28,6 +28,7 @@ class CategoryController extends Controller
     public function index(): Response
     {
         $categories = auth()->user()
+            ->activeSpace()
             ->categories()
             ->forDisplay()
             ->get();
@@ -106,7 +107,8 @@ class CategoryController extends Controller
     {
         if (! str_contains($exception->getMessage(), 'categories_user_id_name_unique')
             && ! str_contains($exception->getMessage(), 'categories_user_id_name_active_unique')
-            && ! str_contains($exception->getMessage(), 'categories_user_id_parent_name_active_unique')) {
+            && ! str_contains($exception->getMessage(), 'categories_user_id_parent_name_active_unique')
+            && ! str_contains($exception->getMessage(), 'categories_space_id_parent_name_active_unique')) {
             throw $exception;
         }
 
diff --git a/app/Http/Controllers/Settings/LabelController.php b/app/Http/Controllers/Settings/LabelController.php
index b02cec41..dd7f26f7 100644
--- a/app/Http/Controllers/Settings/LabelController.php
+++ b/app/Http/Controllers/Settings/LabelController.php
@@ -22,6 +22,7 @@ class LabelController extends Controller
     public function index(): Response
     {
         $labels = auth()->user()
+            ->activeSpace()
             ->labels()
             ->orderBy('name')
             ->get();
diff --git a/app/Http/Controllers/SpaceController.php b/app/Http/Controllers/SpaceController.php
new file mode 100644
index 00000000..02505a57
--- /dev/null
+++ b/app/Http/Controllers/SpaceController.php
@@ -0,0 +1,104 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Actions\CreateDefaultCategories;
+use App\Features\Spaces;
+use App\Http\Requests\StoreSpaceRequest;
+use App\Http\Requests\UpdateSpaceRequest;
+use App\Models\Space;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\DB;
+use Inertia\Inertia;
+use Inertia\Response;
+use Laravel\Pennant\Feature;
+
+class SpaceController extends Controller
+{
+    /**
+     * The spaces management settings page. The list itself is shared globally
+     * (see HandleInertiaRequests), so this only needs to render the page.
+     */
+    public function index(): Response
+    {
+        return Inertia::render('settings/spaces');
+    }
+
+    /**
+     * Create a new space, seed it with the default categories and switch to it.
+     */
+    public function store(StoreSpaceRequest $request): RedirectResponse
+    {
+        $user = $request->user();
+
+        $space = DB::transaction(function () use ($user, $request): Space {
+            $space = $user->ownedSpaces()->create([
+                'name' => $request->validated('name'),
+                'personal' => false,
+            ]);
+
+            app(CreateDefaultCategories::class)->handle($user, $space);
+
+            return $space;
+        });
+
+        $user->forceFill(['current_space_id' => $space->id])->save();
+
+        return back();
+    }
+
+    /**
+     * Rename a space (owner only; the personal space name is fixed).
+     */
+    public function update(UpdateSpaceRequest $request, Space $space): RedirectResponse
+    {
+        $space->update(['name' => $request->validated('name')]);
+
+        return back();
+    }
+
+    /**
+     * Delete a space the user owns. The personal space is permanent, and a space
+     * that still holds accounts must be emptied first — financial data is never
+     * deleted implicitly.
+     */
+    public function destroy(Request $request, Space $space): RedirectResponse
+    {
+        $user = $request->user();
+
+        abort_unless(
+            ! $space->personal
+                && $space->owner_id === $user->id
+                && Feature::for($user)->active(Spaces::class),
+            403,
+        );
+
+        if ($space->accounts()->exists()) {
+            return back()->with('error', __('Remove or move this space\'s accounts before deleting it.'));
+        }
+
+        if ($user->current_space_id === $space->id) {
+            $user->forceFill(['current_space_id' => $user->personalSpace->id])->save();
+        }
+
+        $space->delete();
+
+        return back();
+    }
+
+    /**
+     * Switch the active space. Any space the user owns or belongs to is allowed;
+     * the personal space is always reachable so this never requires the flag.
+     */
+    public function select(Request $request, Space $space): RedirectResponse
+    {
+        $user = $request->user();
+
+        abort_unless($space->hasMember($user), 403);
+
+        $user->forceFill(['current_space_id' => $space->id])->save();
+
+        return back();
+    }
+}
diff --git a/app/Http/Controllers/SubscriptionController.php b/app/Http/Controllers/SubscriptionController.php
index 39e6db5f..64422fd7 100644
--- a/app/Http/Controllers/SubscriptionController.php
+++ b/app/Http/Controllers/SubscriptionController.php
@@ -33,7 +33,8 @@ class SubscriptionController extends Controller
             return redirect()->route('dashboard');
         }
 
-        $hasBankConnections = $user->bankingConnections()->exists();
+        $space = $user->activeSpace();
+        $hasBankConnections = $space->bankingConnections()->exists();
         $canUseFreePlan = ! $hasBankConnections && ! $user->hasActiveAiConsent();
 
         // Mark the paywall as seen so the middleware stops redirecting here.
@@ -56,7 +57,8 @@ class SubscriptionController extends Controller
      */
     private function getUserStats(User $user): array
     {
-        $accounts = $user->accounts()->get();
+        $space = $user->activeSpace();
+        $accounts = $space->accounts()->get();
 
         $balancesByCurrency = [];
         foreach ($accounts as $account) {
@@ -74,9 +76,9 @@ class SubscriptionController extends Controller
 
         return [
             'accountsCount' => $accounts->count(),
-            'transactionsCount' => $user->transactions()->count(),
-            'categoriesCount' => $user->categories()->count(),
-            'automationRulesCount' => $user->automationRules()->count(),
+            'transactionsCount' => $space->transactions()->count(),
+            'categoriesCount' => $space->categories()->count(),
+            'automationRulesCount' => $space->automationRules()->count(),
             'balancesByCurrency' => $balancesByCurrency,
         ];
     }
diff --git a/app/Http/Controllers/Sync/TransactionSyncController.php b/app/Http/Controllers/Sync/TransactionSyncController.php
index 448fe8eb..cb0bd84a 100644
--- a/app/Http/Controllers/Sync/TransactionSyncController.php
+++ b/app/Http/Controllers/Sync/TransactionSyncController.php
@@ -3,7 +3,6 @@
 namespace App\Http\Controllers\Sync;
 
 use App\Http\Controllers\Controller;
-use App\Models\Transaction;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 
@@ -15,8 +14,7 @@ class TransactionSyncController extends Controller
      */
     public function index(Request $request): JsonResponse
     {
-        $query = Transaction::query()
-            ->where('user_id', $request->user()->id);
+        $query = $request->user()->activeSpace()->transactions();
 
         if ($request->has('since')) {
             $query->where('updated_at', '>', $request->input('since'));
diff --git a/app/Http/Controllers/TransactionController.php b/app/Http/Controllers/TransactionController.php
index da086fc8..b607fcc7 100644
--- a/app/Http/Controllers/TransactionController.php
+++ b/app/Http/Controllers/TransactionController.php
@@ -7,11 +7,7 @@ use App\Http\Requests\BulkUpdateTransactionsRequest;
 use App\Http\Requests\IndexTransactionRequest;
 use App\Http\Requests\StoreTransactionRequest;
 use App\Http\Requests\UpdateTransactionRequest;
-use App\Models\Account;
-use App\Models\AutomationRule;
 use App\Models\Bank;
-use App\Models\Category;
-use App\Models\Label;
 use App\Models\Transaction;
 use App\Services\Ai\CategoryOverrideHandler;
 use App\Services\ManualBalanceAdjuster;
@@ -28,6 +24,7 @@ class TransactionController extends Controller
     public function index(IndexTransactionRequest $request): Response
     {
         $user = $request->user();
+        $space = $user->activeSpace();
         $validated = $request->validated();
 
         $lastVisitAt = $user->transactions_last_visited_at;
@@ -53,8 +50,9 @@ class TransactionController extends Controller
             'search' => $validated['search'] ?? null,
         ], fn ($value) => $value !== null);
 
-        $query = Transaction::query()
-            ->where('user_id', $user->id)
+        $filters['space_id'] = $space->id;
+
+        $query = $space->transactions()
             ->with(['account.bank', 'category', 'labels', 'categorizedByRule:id,origin'])
             ->applyFilters($filters);
 
@@ -99,13 +97,11 @@ class TransactionController extends Controller
             'sort' => $sortParam,
         ];
 
-        $categories = Category::query()
-            ->where('user_id', $user->id)
+        $categories = $space->categories()
             ->forDisplay()
             ->get();
 
-        $accounts = Account::query()
-            ->where('user_id', $user->id)
+        $accounts = $space->accounts()
             ->with('bank')
             ->orderBy('name')
             ->get();
@@ -115,13 +111,11 @@ class TransactionController extends Controller
             ->orderBy('name')
             ->get();
 
-        $labels = Label::query()
-            ->where('user_id', $user->id)
+        $labels = $space->labels()
             ->orderBy('name')
             ->get();
 
-        $automationRules = AutomationRule::query()
-            ->where('user_id', $user->id)
+        $automationRules = $space->automationRules()
             ->with(['category', 'labels'])
             ->orderBy('priority')
             ->get();
@@ -143,14 +137,13 @@ class TransactionController extends Controller
     public function categorize(Request $request): Response
     {
         $user = $request->user();
+        $space = $user->activeSpace();
 
-        $categories = Category::query()
-            ->where('user_id', $user->id)
+        $categories = $space->categories()
             ->forDisplay()
             ->get();
 
-        $accounts = Account::query()
-            ->where('user_id', $user->id)
+        $accounts = $space->accounts()
             ->with('bank')
             ->orderBy('name')
             ->get();
@@ -160,13 +153,11 @@ class TransactionController extends Controller
             ->orderBy('name')
             ->get();
 
-        $labels = Label::query()
-            ->where('user_id', $user->id)
+        $labels = $space->labels()
             ->orderBy('name')
             ->get();
 
-        $transactions = Transaction::query()
-            ->where('user_id', $user->id)
+        $transactions = $space->transactions()
             ->whereNull('category_id')
             ->with(['account.bank', 'labels'])
             ->orderBy('transaction_date', 'desc')
@@ -304,10 +295,15 @@ class TransactionController extends Controller
     public function bulkUpdate(BulkUpdateTransactionsRequest $request): JsonResponse
     {
         $user = $request->user();
+        $space = $user->activeSpace();
         $transactionIds = $request->input('transaction_ids');
         $filters = $request->input('filters');
 
-        $query = Transaction::query()->where('user_id', $user->id);
+        if (is_array($filters)) {
+            $filters['space_id'] = $space->id;
+        }
+
+        $query = $space->transactions();
 
         if ($transactionIds && count($transactionIds) > 0) {
             $query->whereIn('id', $transactionIds);
@@ -357,7 +353,7 @@ class TransactionController extends Controller
         }
 
         if (! empty($updateData)) {
-            $updateQuery = Transaction::query()->where('user_id', $user->id);
+            $updateQuery = $space->transactions();
             if ($transactionIds && count($transactionIds) > 0) {
                 $updateQuery->whereIn('id', $transactionIds);
             } elseif ($filters !== null) {
diff --git a/app/Http/Middleware/HandleInertiaRequests.php b/app/Http/Middleware/HandleInertiaRequests.php
index a7991136..bca2ac17 100644
--- a/app/Http/Middleware/HandleInertiaRequests.php
+++ b/app/Http/Middleware/HandleInertiaRequests.php
@@ -5,6 +5,7 @@ namespace App\Http\Middleware;
 use App\Enums\BankingConnectionStatus;
 use App\Enums\BankingProvider;
 use App\Features\CalculateBalancesOnImport;
+use App\Features\Spaces;
 use App\Jobs\PurgeResidualEncryptionArtifactsJob;
 use App\Models\BankingConnection;
 use App\Services\CurrencyOptions;
@@ -48,6 +49,7 @@ class HandleInertiaRequests extends Middleware
         [$message, $author] = str(Inspiring::quotes()->random())->explode('-');
 
         $user = $request->user();
+        $space = $user?->activeSpace();
         $isDemoAccount = $user?->isDemoAccount() && ! app()->environment('local');
         $isDemoQuery = $request->query('demo') === '1';
 
@@ -105,7 +107,24 @@ class HandleInertiaRequests extends Middleware
             'includeRealEstateInNetWorthChart' => $user?->setting->include_real_estate_in_net_worth_chart ?? true,
             'sidebarOpen' => ! $request->hasCookie('sidebar_state') || $request->cookie('sidebar_state') === 'true',
             'features' => $this->resolveFeatureFlags(),
-            'expiredBankingConnections' => fn () => $user ? $user->bankingConnections()
+            'currentSpace' => $space ? [
+                'id' => $space->id,
+                'name' => $space->personal ? __('Personal') : $space->name,
+                'personal' => $space->personal,
+                'is_owner' => $space->owner_id === $user->id,
+            ] : null,
+            // Only the spaces UI needs the full list; skip the query entirely for
+            // everyone still on their single, invisible personal space.
+            'spaces' => fn () => $user && Feature::for($user)->active(Spaces::class)
+                ? $user->accessibleSpaces()
+                    ->map(fn ($accessibleSpace): array => [
+                        'id' => $accessibleSpace->id,
+                        'name' => $accessibleSpace->personal ? __('Personal') : $accessibleSpace->name,
+                        'personal' => $accessibleSpace->personal,
+                        'is_owner' => $accessibleSpace->owner_id === $user->id,
+                    ])->all()
+                : [],
+            'expiredBankingConnections' => fn () => $space ? $space->bankingConnections()
                 ->where('provider', BankingProvider::EnableBanking)
                 ->where(function ($query) {
                     $query->where('status', BankingConnectionStatus::Expired)
@@ -124,7 +143,7 @@ class HandleInertiaRequests extends Middleware
                     'valid_until' => $connection->valid_until?->toIso8601String(),
                     'reconnect_url' => route('open-banking.reconnect', $connection),
                 ]) : [],
-            'bankingConnections' => fn () => $user ? $user->bankingConnections()
+            'bankingConnections' => fn () => $space ? $space->bankingConnections()
                 ->get(['id', 'aspsp_name', 'provider', 'status'])
                 ->map(fn (BankingConnection $connection): array => [
                     'id' => $connection->id,
@@ -132,28 +151,28 @@ class HandleInertiaRequests extends Middleware
                     'provider' => $connection->provider->value,
                     'status' => $connection->status->value,
                 ]) : [],
-            'accounts' => fn () => $user ? $user->accounts()
+            'accounts' => fn () => $space ? $space->accounts()
                 ->with(['bank', 'realEstateDetail:id,account_id,linked_loan_account_id'])
                 ->orderBy('name')
                 ->get()
                 ->makeHidden('realEstateDetail') : [],
-            'categories' => fn () => $user ? $user->categories()
+            'categories' => fn () => $space ? $space->categories()
                 ->forDisplay()
                 ->get() : [],
             'banks' => fn () => $user ? $user->banks()
                 ->orderBy('name')
                 ->get() : [],
-            'automationRules' => function () use ($user) {
-                if (! $user) {
+            'automationRules' => function () use ($space) {
+                if (! $space) {
                     return [];
                 }
 
-                return $user->automationRules()
+                return $space->automationRules()
                     ->with(['category', 'labels'])
                     ->orderBy('priority')
                     ->get();
             },
-            'labels' => fn () => $user ? $user->labels()
+            'labels' => fn () => $space ? $space->labels()
                 ->orderBy('name')
                 ->get() : [],
             'hasEncryptedAccounts' => $hasEncryptedAccounts,
@@ -179,16 +198,19 @@ class HandleInertiaRequests extends Middleware
             return [
                 'cashflow' => true,
                 'calculateBalancesOnImport' => false,
+                'spaces' => false,
             ];
         }
 
         $features = Feature::for($user)->values([
             CalculateBalancesOnImport::class,
+            Spaces::class,
         ]);
 
         return [
             'cashflow' => true,
             'calculateBalancesOnImport' => $features[CalculateBalancesOnImport::class] !== false,
+            'spaces' => $features[Spaces::class] !== false,
         ];
     }
 
diff --git a/app/Http/Middleware/ResolveActiveSpace.php b/app/Http/Middleware/ResolveActiveSpace.php
new file mode 100644
index 00000000..4f1f7471
--- /dev/null
+++ b/app/Http/Middleware/ResolveActiveSpace.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * Resolve (and repair) the authenticated user's active space before controllers
+ * run, so every read scoped to `$user->activeSpace()` and every write that fills
+ * `space_id` from `current_space_id` sees a valid pointer — even right after a
+ * space was deleted or a membership was revoked.
+ */
+class ResolveActiveSpace
+{
+    public function handle(Request $request, Closure $next): Response
+    {
+        $request->user()?->activeSpace();
+
+        return $next($request);
+    }
+}
diff --git a/app/Http/Requests/StoreSpaceRequest.php b/app/Http/Requests/StoreSpaceRequest.php
new file mode 100644
index 00000000..5809b7df
--- /dev/null
+++ b/app/Http/Requests/StoreSpaceRequest.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Http\Requests;
+
+use App\Features\Spaces;
+use Illuminate\Foundation\Http\FormRequest;
+use Laravel\Pennant\Feature;
+
+class StoreSpaceRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        return $this->user() !== null
+            && Feature::for($this->user())->active(Spaces::class);
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function rules(): array
+    {
+        return [
+            'name' => ['required', 'string', 'max:255'],
+        ];
+    }
+}
diff --git a/app/Http/Requests/UpdateSpaceRequest.php b/app/Http/Requests/UpdateSpaceRequest.php
new file mode 100644
index 00000000..59fd9218
--- /dev/null
+++ b/app/Http/Requests/UpdateSpaceRequest.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace App\Http\Requests;
+
+use App\Features\Spaces;
+use App\Models\Space;
+use Illuminate\Foundation\Http\FormRequest;
+use Laravel\Pennant\Feature;
+
+class UpdateSpaceRequest extends FormRequest
+{
+    public function authorize(): bool
+    {
+        $space = $this->route('space');
+
+        return $space instanceof Space
+            && ! $space->personal
+            && $space->owner_id === $this->user()?->id
+            && Feature::for($this->user())->active(Spaces::class);
+    }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function rules(): array
+    {
+        return [
+            'name' => ['required', 'string', 'max:255'],
+        ];
+    }
+}
diff --git a/app/Models/Transaction.php b/app/Models/Transaction.php
index 84d3b169..f3329076 100644
--- a/app/Models/Transaction.php
+++ b/app/Models/Transaction.php
@@ -282,10 +282,10 @@ class Transaction extends Model
                 $realIds = $ids->reject(fn ($id) => $id === 'uncategorized')->values()->all();
 
                 if ($realIds !== []) {
-                    $userId = $filters['user_id'] ?? Category::query()->whereIn('id', $realIds)->value('user_id');
+                    $spaceId = $filters['space_id'] ?? Category::query()->whereIn('id', $realIds)->value('space_id');
 
-                    if ($userId !== null) {
-                        $realIds = app(CategoryTree::class)->expand($userId, $realIds);
+                    if ($spaceId !== null) {
+                        $realIds = app(CategoryTree::class)->expand($spaceId, $realIds);
                     }
                 }
             }
diff --git a/app/Models/User.php b/app/Models/User.php
index 27d4a66b..c9c236ed 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -230,7 +230,8 @@ class User extends Authenticatable implements HasLocalePreference, MustVerifyEma
      */
     public function activeSpace(): Space
     {
-        if ($this->resolvedActiveSpace !== null) {
+        if ($this->resolvedActiveSpace !== null
+            && $this->resolvedActiveSpace->id === $this->current_space_id) {
             return $this->resolvedActiveSpace;
         }
 
diff --git a/app/Policies/Concerns/HandlesUserOwnership.php b/app/Policies/Concerns/HandlesUserOwnership.php
index 3a4b2a8e..805a32b6 100644
--- a/app/Policies/Concerns/HandlesUserOwnership.php
+++ b/app/Policies/Concerns/HandlesUserOwnership.php
@@ -36,7 +36,7 @@ trait HandlesUserOwnership
      */
     public function update(User $user, Model $model): bool
     {
-        return $user->id === $model->getAttribute('user_id');
+        return $this->userCanAccess($user, $model);
     }
 
     /**
@@ -44,7 +44,24 @@ trait HandlesUserOwnership
      */
     public function delete(User $user, Model $model): bool
     {
-        return $user->id === $model->getAttribute('user_id');
+        return $this->userCanAccess($user, $model);
+    }
+
+    /**
+     * A space-owned model is accessible to any member of its space; models that
+     * predate spaces (or child records without a space_id) fall back to the
+     * legacy creator check.
+     */
+    protected function userCanAccess(User $user, Model $model): bool
+    {
+        $spaceId = $model->getAttribute('space_id');
+
+        if ($spaceId === null) {
+            return $user->id === $model->getAttribute('user_id');
+        }
+
+        return $user->current_space_id === $spaceId
+            || $user->accessibleSpaces()->contains('id', $spaceId);
     }
 
     /**
diff --git a/app/Services/BudgetTransactionService.php b/app/Services/BudgetTransactionService.php
index adf39b80..a8807dbd 100644
--- a/app/Services/BudgetTransactionService.php
+++ b/app/Services/BudgetTransactionService.php
@@ -16,9 +16,9 @@ class BudgetTransactionService
 
     public function assignTransaction(Transaction $transaction): void
     {
-        $userId = $transaction->user_id;
+        $spaceId = $transaction->space_id;
 
-        if (! $userId) {
+        if (! $spaceId) {
             return;
         }
 
@@ -31,13 +31,13 @@ class BudgetTransactionService
         // transaction matches a budget when any of its category's ancestors
         // (or itself) is attached to that budget.
         $categoryMatchIds = $transaction->category_id
-            ? $this->tree->ancestorAndSelfIds($userId, $transaction->category_id)
+            ? $this->tree->ancestorAndSelfIds($spaceId, $transaction->category_id)
             : [];
 
         // Find budget periods that potentially match this transaction.
         $budgetPeriods = BudgetPeriod::query()
-            ->whereHas('budget', function ($query) use ($categoryMatchIds, $transactionLabelIds, $userId) {
-                $query->where('user_id', $userId)
+            ->whereHas('budget', function ($query) use ($categoryMatchIds, $transactionLabelIds, $spaceId) {
+                $query->where('space_id', $spaceId)
                     ->where(function ($q) use ($categoryMatchIds, $transactionLabelIds) {
                         $q->whereHas('categories', function ($cq) use ($categoryMatchIds) {
                             $cq->whereIn('categories.id', $categoryMatchIds);
@@ -72,7 +72,7 @@ class BudgetTransactionService
 
         $matchingPeriodIds = array_merge(
             $matchingPeriodIds,
-            $this->catchAllPeriodIds($transaction, $userId, $categoryMatchIds),
+            $this->catchAllPeriodIds($transaction, $spaceId, $categoryMatchIds),
         );
 
         // Apply changes atomically so concurrent workers cannot leave the
@@ -122,11 +122,11 @@ class BudgetTransactionService
         $assignedCount = 0;
 
         // Tracking a parent category also tracks its children's spending.
-        $categoryIds = collect($this->tree->expand($budget->user_id, $budget->categories->pluck('id')->all()));
+        $categoryIds = collect($this->tree->expand($budget->space_id, $budget->categories->pluck('id')->all()));
         $labelIds = $budget->labels->pluck('id');
 
         Log::info('Building query for historical transactions', [
-            'user_id' => $budget->user_id,
+            'space_id' => $budget->space_id,
             'category_ids' => $categoryIds->all(),
             'label_ids' => $labelIds->all(),
             'start_date' => $period->start_date->toDateString(),
@@ -135,16 +135,16 @@ class BudgetTransactionService
 
         // Build the query for matching transactions
         $query = Transaction::query()
-            ->where('user_id', $budget->user_id)
+            ->where('space_id', $budget->space_id)
             ->whereBetween('transaction_date', [$period->start_date, $period->end_date])
             ->withoutTrashed();
 
         if ($budget->is_catch_all) {
             // A catch-all budget absorbs every expense whose category is not
-            // already tracked by one of the user's other budgets.
+            // already tracked by one of the space's other budgets.
             $claimedCategoryIds = $this->tree->expand(
-                $budget->user_id,
-                $this->claimedCategoryIds($budget->user_id),
+                $budget->space_id,
+                $this->claimedCategoryIds($budget->space_id),
             );
 
             $query->whereNotNull('category_id')
@@ -200,7 +200,7 @@ class BudgetTransactionService
      * @param  array<int, string>  $categoryMatchIds  the transaction category and its ancestors
      * @return array<int, string>
      */
-    private function catchAllPeriodIds(Transaction $transaction, string $userId, array $categoryMatchIds): array
+    private function catchAllPeriodIds(Transaction $transaction, string $spaceId, array $categoryMatchIds): array
     {
         if ($transaction->category_id === null) {
             return [];
@@ -212,13 +212,13 @@ class BudgetTransactionService
             return [];
         }
 
-        if (array_intersect($categoryMatchIds, $this->claimedCategoryIds($userId)) !== []) {
+        if (array_intersect($categoryMatchIds, $this->claimedCategoryIds($spaceId)) !== []) {
             return [];
         }
 
         return BudgetPeriod::query()
-            ->whereHas('budget', function ($query) use ($userId) {
-                $query->where('user_id', $userId)->where('is_catch_all', true);
+            ->whereHas('budget', function ($query) use ($spaceId) {
+                $query->where('space_id', $spaceId)->where('is_catch_all', true);
             })
             ->where('start_date', '<=', $transaction->transaction_date)
             ->where('end_date', '>=', $transaction->transaction_date)
@@ -227,14 +227,14 @@ class BudgetTransactionService
     }
 
     /**
-     * Category ids directly tracked by the user's non-catch-all budgets.
+     * Category ids directly tracked by the space's non-catch-all budgets.
      *
      * @return array<int, string>
      */
-    private function claimedCategoryIds(string $userId): array
+    private function claimedCategoryIds(string $spaceId): array
     {
         return Budget::query()
-            ->where('user_id', $userId)
+            ->where('space_id', $spaceId)
             ->where('is_catch_all', false)
             ->with('categories:id')
             ->get()
diff --git a/app/Services/CategorySpendingService.php b/app/Services/CategorySpendingService.php
index 3e41836d..e3e64439 100644
--- a/app/Services/CategorySpendingService.php
+++ b/app/Services/CategorySpendingService.php
@@ -20,10 +20,10 @@ class CategorySpendingService
      * become the rows (plus a direct node for transactions sitting on the
      * parent itself). Soft-deleted categories are excluded.
      */
-    public function forPeriod(string $userId, Carbon $from, Carbon $to, ?string $drillParentId = null): Collection
+    public function forPeriod(string $spaceId, Carbon $from, Carbon $to, ?string $drillParentId = null): Collection
     {
         $perCategory = Transaction::query()
-            ->where('transactions.user_id', $userId)
+            ->where('transactions.space_id', $spaceId)
             ->whereBetween('transactions.transaction_date', [$from, $to])
             ->join('categories', function ($join) {
                 $join->on('transactions.category_id', '=', 'categories.id')
@@ -41,7 +41,7 @@ class CategorySpendingService
             ->values()
             ->all();
 
-        return collect($this->tree->rollUp($perCategory, $userId, $drillParentId))
+        return collect($this->tree->rollUp($perCategory, $spaceId, $drillParentId))
             ->filter(fn (array $item): bool => $item['amount'] > 0)
             ->values();
     }
diff --git a/app/Services/CategoryTree.php b/app/Services/CategoryTree.php
index cd427776..fba4e57b 100644
--- a/app/Services/CategoryTree.php
+++ b/app/Services/CategoryTree.php
@@ -17,7 +17,7 @@ class CategoryTree
      * @param  array<int, string>  $ids
      * @return array<int, string>
      */
-    public function expand(string $userId, array $ids): array
+    public function expand(string $spaceId, array $ids): array
     {
         $ids = array_values(array_unique(array_filter($ids)));
 
@@ -30,7 +30,7 @@ class CategoryTree
 
         for ($level = 1; $level < Category::MAX_DEPTH; $level++) {
             $childIds = Category::query()
-                ->where('user_id', $userId)
+                ->where('space_id', $spaceId)
                 ->whereIn('parent_id', $frontier)
                 ->pluck('id')
                 ->all();
@@ -56,7 +56,7 @@ class CategoryTree
     public function descendantIds(Category $category): array
     {
         return array_values(array_diff(
-            $this->expand($category->user_id, [$category->id]),
+            $this->expand($category->space_id, [$category->id]),
             [$category->id],
         ));
     }
@@ -66,11 +66,11 @@ class CategoryTree
      *
      * @return array<int, string>
      */
-    public function ancestorAndSelfIds(string $userId, string $categoryId): array
+    public function ancestorAndSelfIds(string $spaceId, string $categoryId): array
     {
         $ids = [$categoryId];
         $parentId = Category::query()
-            ->where('user_id', $userId)
+            ->where('space_id', $spaceId)
             ->whereKey($categoryId)
             ->value('parent_id');
 
@@ -79,7 +79,7 @@ class CategoryTree
         while ($parentId !== null && $guard++ < Category::MAX_DEPTH) {
             $ids[] = $parentId;
             $parentId = Category::query()
-                ->where('user_id', $userId)
+                ->where('space_id', $spaceId)
                 ->whereKey($parentId)
                 ->value('parent_id');
         }
@@ -97,7 +97,7 @@ class CategoryTree
 
         while ($parentId !== null && $depth <= Category::MAX_DEPTH) {
             $parentId = Category::query()
-                ->where('user_id', $category->user_id)
+                ->where('space_id', $category->space_id)
                 ->where('id', $parentId)
                 ->value('parent_id');
 
@@ -118,7 +118,7 @@ class CategoryTree
 
         for ($level = 1; $level < Category::MAX_DEPTH; $level++) {
             $childIds = Category::query()
-                ->where('user_id', $category->user_id)
+                ->where('space_id', $category->space_id)
                 ->whereIn('parent_id', $frontier)
                 ->pluck('id')
                 ->all();
@@ -145,10 +145,10 @@ class CategoryTree
      * @param  array<int, array{category_id: ?string, category: Category|null, amount: int}>  $categorized
      * @return array<int, array{category_id: ?string, category: Category|null, amount: int, has_children: bool, is_direct: bool}>
      */
-    public function rollUp(array $categorized, string $userId, ?string $drillParentId): array
+    public function rollUp(array $categorized, string $spaceId, ?string $drillParentId): array
     {
         $categories = Category::query()
-            ->where('user_id', $userId)
+            ->where('space_id', $spaceId)
             ->forDisplay()
             ->get()
             ->keyBy('id');
@@ -230,10 +230,10 @@ class CategoryTree
      * @param  array<int, array{category_id: ?string, amount: int}>  $categorized
      * @return array<int, array{category_id: string, category: Category, amount: int, children: array<int, array{category_id: string, category: Category, amount: int}>}>
      */
-    public function spendingBreakdown(array $categorized, string $userId): array
+    public function spendingBreakdown(array $categorized, string $spaceId): array
     {
         $categories = Category::query()
-            ->where('user_id', $userId)
+            ->where('space_id', $spaceId)
             ->forDisplay()
             ->get()
             ->keyBy('id');
@@ -380,7 +380,7 @@ class CategoryTree
         }
 
         Category::query()
-            ->where('user_id', $category->user_id)
+            ->where('space_id', $category->space_id)
             ->whereIn('id', $descendantIds)
             ->update([
                 'type' => $category->type,
@@ -397,12 +397,12 @@ class CategoryTree
         $ids = [$category->id, ...$this->descendantIds($category)];
 
         Transaction::query()
-            ->where('user_id', $category->user_id)
+            ->where('space_id', $category->space_id)
             ->whereIn('category_id', $ids)
             ->update(['category_id' => null]);
 
         Category::query()
-            ->where('user_id', $category->user_id)
+            ->where('space_id', $category->space_id)
             ->whereIn('id', $ids)
             ->delete();
     }
diff --git a/bootstrap/app.php b/bootstrap/app.php
index 9a402ed2..6d9fc68b 100644
--- a/bootstrap/app.php
+++ b/bootstrap/app.php
@@ -5,6 +5,7 @@ use App\Http\Middleware\EnsureOnboardingComplete;
 use App\Http\Middleware\EnsureUserIsSubscribed;
 use App\Http\Middleware\HandleAppearance;
 use App\Http\Middleware\HandleInertiaRequests;
+use App\Http\Middleware\ResolveActiveSpace;
 use App\Http\Middleware\SetLocale;
 use App\Http\Middleware\SetSentryUser;
 use App\Http\Middleware\TrackLastActiveAt;
@@ -44,6 +45,7 @@ return Application::configure(basePath: dirname(__DIR__))
             HandleAppearance::class,
             SetLocale::class,
             SetSentryUser::class,
+            ResolveActiveSpace::class,
             HandleInertiaRequests::class,
             AddLinkHeadersForPreloadedAssets::class,
             TrackLastActiveAt::class,
diff --git a/database/factories/TransactionFactory.php b/database/factories/TransactionFactory.php
index 772c1cc6..f1317f9e 100644
--- a/database/factories/TransactionFactory.php
+++ b/database/factories/TransactionFactory.php
@@ -36,6 +36,33 @@ class TransactionFactory extends Factory
         ];
     }
 
+    /**
+     * Keep fixtures coherent with the multi-tenant model: a transaction, its
+     * account and its space share one owner. When a caller sets a user_id but
+     * lets the account default (or wires an account owned by someone else), we
+     * realign the account to that user so space scoping in tests mirrors
+     * production, where transaction.space_id always equals account.space_id.
+     */
+    public function configure(): static
+    {
+        return $this->afterMaking(function (Transaction $transaction): void {
+            if ($transaction->user_id === null) {
+                return;
+            }
+
+            $account = $transaction->account;
+
+            if ($account !== null && $account->user_id !== $transaction->user_id) {
+                $account->forceFill([
+                    'user_id' => $transaction->user_id,
+                    'space_id' => User::query()->whereKey($transaction->user_id)->value('current_space_id'),
+                ])->save();
+
+                $transaction->setRelation('account', $account);
+            }
+        });
+    }
+
     public function imported(): static
     {
         return $this->state(fn (array $attributes) => [
diff --git a/database/migrations/2026_07_06_130000_rescope_unique_indexes_to_space.php b/database/migrations/2026_07_06_130000_rescope_unique_indexes_to_space.php
new file mode 100644
index 00000000..81f72a1a
--- /dev/null
+++ b/database/migrations/2026_07_06_130000_rescope_unique_indexes_to_space.php
@@ -0,0 +1,67 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Category, label and saved-filter names were unique per user. Now that a
+     * user can own several spaces (each seeded with the same default category
+     * names), those constraints must be per space instead — otherwise creating a
+     * second space collides with the first space's categories. Runs after the
+     * backfill, so space_id is already populated on every existing row.
+     *
+     * The old composite uniques also served as the index MySQL requires for the
+     * `user_id` foreign key, so we add a plain `user_id` index before dropping
+     * them (and drop it again on rollback once the composite is restored).
+     */
+    public function up(): void
+    {
+        Schema::table('categories', function (Blueprint $table) {
+            $table->index('user_id', 'categories_user_id_index');
+            $table->dropUnique('categories_user_id_parent_name_active_unique');
+            $table->unique(
+                ['space_id', 'parent_unique_marker', 'name', 'active_unique_marker'],
+                'categories_space_id_parent_name_active_unique',
+            );
+        });
+
+        Schema::table('labels', function (Blueprint $table) {
+            $table->index('user_id', 'labels_user_id_index');
+            $table->dropUnique('labels_user_id_name_deleted_at_unique');
+            $table->unique(['space_id', 'name', 'deleted_at'], 'labels_space_id_name_deleted_at_unique');
+        });
+
+        Schema::table('saved_filters', function (Blueprint $table) {
+            $table->index('user_id', 'saved_filters_user_id_index');
+            $table->dropUnique('saved_filters_user_id_name_unique');
+            $table->unique(['space_id', 'name'], 'saved_filters_space_id_name_unique');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('categories', function (Blueprint $table) {
+            $table->dropUnique('categories_space_id_parent_name_active_unique');
+            $table->unique(
+                ['user_id', 'parent_unique_marker', 'name', 'active_unique_marker'],
+                'categories_user_id_parent_name_active_unique',
+            );
+            $table->dropIndex('categories_user_id_index');
+        });
+
+        Schema::table('labels', function (Blueprint $table) {
+            $table->dropUnique('labels_space_id_name_deleted_at_unique');
+            $table->unique(['user_id', 'name', 'deleted_at'], 'labels_user_id_name_deleted_at_unique');
+            $table->dropIndex('labels_user_id_index');
+        });
+
+        Schema::table('saved_filters', function (Blueprint $table) {
+            $table->dropUnique('saved_filters_space_id_name_unique');
+            $table->unique(['user_id', 'name'], 'saved_filters_user_id_name_unique');
+            $table->dropIndex('saved_filters_user_id_index');
+        });
+    }
+};
diff --git a/lang/es.json b/lang/es.json
index 8facad96..4ffe8c74 100644
--- a/lang/es.json
+++ b/lang/es.json
@@ -68,7 +68,6 @@
     "You have reached your monthly limit of :count integration actions. Try again next month.": "Has alcanzado tu límite mensual de :count acciones de integración. Inténtalo de nuevo el mes que viene.",
     "Remove one vote": "Quitar un voto",
     "Categorized by AI": "Categorizado por IA",
-    "Let AI categorize your transactions": "Deja que la IA categorice tus transacciones",
     "Categorized by AI with :confidence% confident": "Categorizado por IA con un :confidence % de confianza",
     "Only show AI guesses": "Mostrar solo sugerencias de IA",
     "Created by AI": "Creado por IA",
@@ -2217,5 +2216,23 @@
     "See your categorised transactions": "Ver tus transacciones categorizadas",
     "Private by design, always": "Privado por diseño, siempre",
     "Turning on AI never changes who owns your data — you do. We only use it to help you understand your own finances, and you can revoke this consent at any time from your settings.": "Activar la IA nunca cambia quién es el dueño de tus datos: lo eres tú. Solo la usamos para ayudarte a entender tus propias finanzas, y puedes revocar este consentimiento cuando quieras desde tus ajustes.",
-    "If you have any questions, **just reply to this email**. We personally read every message.": "Si tienes cualquier duda, **responde a este correo**. Leemos personalmente cada mensaje."
+    "If you have any questions, **just reply to this email**. We personally read every message.": "Si tienes cualquier duda, **responde a este correo**. Leemos personalmente cada mensaje.",
+    "Personal": "Personal",
+    "Personal space": "Espacio personal",
+    "Space": "Espacio",
+    "Spaces": "Espacios",
+    "Create space": "Crear espacio",
+    "Manage spaces": "Gestionar espacios",
+    "A space groups its own accounts, transactions, categories and budgets, kept separate from your other spaces.": "Un espacio agrupa sus propias cuentas, transacciones, categorías y presupuestos, separados de tus otros espacios.",
+    "e.g. My Company": "p. ej. Mi Empresa",
+    "Delete this space? This cannot be undone.": "¿Eliminar este espacio? Esta acción no se puede deshacer.",
+    "Each space keeps its own accounts, transactions, categories and budgets separate.": "Cada espacio mantiene separadas sus propias cuentas, transacciones, categorías y presupuestos.",
+    "Active": "Activo",
+    "Switch": "Cambiar",
+    "Rename": "Renombrar",
+    "Rename space": "Renombrar espacio",
+    "Remove or move this space's accounts before deleting it.": "Elimina o mueve las cuentas de este espacio antes de borrarlo.",
+    "Spaces settings": "Configuración de espacios",
+    "Delete space": "Eliminar espacio",
+    "This space has no accounts yet.": "Este espacio aún no tiene cuentas."
 }
diff --git a/resources/js/components/app-sidebar.tsx b/resources/js/components/app-sidebar.tsx
index 3521a4a3..43e50c48 100644
--- a/resources/js/components/app-sidebar.tsx
+++ b/resources/js/components/app-sidebar.tsx
@@ -1,6 +1,7 @@
 import { NavFooter } from '@/components/nav-footer';
 import { NavMain } from '@/components/nav-main';
 import { NavUser } from '@/components/nav-user';
+import { SpaceSwitcher } from '@/components/space-switcher';
 import {
     Sidebar,
     SidebarContent,
@@ -71,6 +72,7 @@ export function AppSidebar() {
                             </SidebarMenuButton>
                         </SidebarMenuItem>
                     </SidebarMenu>
+                    <SpaceSwitcher />
                 </SidebarHeader>
 
                 <SidebarContent>
diff --git a/resources/js/components/space-switcher.tsx b/resources/js/components/space-switcher.tsx
new file mode 100644
index 00000000..03a3ecaf
--- /dev/null
+++ b/resources/js/components/space-switcher.tsx
@@ -0,0 +1,210 @@
+import {
+    index as manageSpaces,
+    select as selectSpace,
+    store as storeSpace,
+} from '@/actions/App/Http/Controllers/SpaceController';
+import { Button } from '@/components/ui/button';
+import {
+    Dialog,
+    DialogContent,
+    DialogDescription,
+    DialogFooter,
+    DialogHeader,
+    DialogTitle,
+} from '@/components/ui/dialog';
+import {
+    DropdownMenu,
+    DropdownMenuContent,
+    DropdownMenuItem,
+    DropdownMenuLabel,
+    DropdownMenuSeparator,
+    DropdownMenuTrigger,
+} from '@/components/ui/dropdown-menu';
+import { Input } from '@/components/ui/input';
+import { Label } from '@/components/ui/label';
+import {
+    SidebarMenu,
+    SidebarMenuButton,
+    SidebarMenuItem,
+    useSidebar,
+} from '@/components/ui/sidebar';
+import { useIsMobile } from '@/hooks/use-mobile';
+import { SharedData } from '@/types';
+import { __ } from '@/utils/i18n';
+import { Link, router, usePage } from '@inertiajs/react';
+import {
+    Building2,
+    Check,
+    ChevronsUpDown,
+    Plus,
+    Settings2,
+    User,
+} from 'lucide-react';
+import { FormEvent, useState } from 'react';
+
+export function SpaceSwitcher() {
+    const { currentSpace, spaces, features } = usePage<SharedData>().props;
+    const { state } = useSidebar();
+    const isMobile = useIsMobile();
+    const [createOpen, setCreateOpen] = useState(false);
+    const [name, setName] = useState('');
+    const [processing, setProcessing] = useState(false);
+
+    // The switcher only exists for accounts with the spaces feature; everyone
+    // else keeps their single, invisible personal space.
+    if (!features.spaces || !currentSpace) {
+        return null;
+    }
+
+    const switchTo = (spaceId: string) => {
+        if (spaceId === currentSpace.id) {
+            return;
+        }
+
+        router.post(selectSpace(spaceId).url, {}, { preserveScroll: false });
+    };
+
+    const createSpace = (event: FormEvent) => {
+        event.preventDefault();
+        setProcessing(true);
+
+        router.post(
+            storeSpace().url,
+            { name },
+            {
+                preserveScroll: true,
+                onFinish: () => setProcessing(false),
+                onSuccess: () => {
+                    setCreateOpen(false);
+                    setName('');
+                },
+            },
+        );
+    };
+
+    return (
+        <SidebarMenu>
+            <SidebarMenuItem>
+                <DropdownMenu>
+                    <DropdownMenuTrigger asChild>
+                        <SidebarMenuButton
+                            size="lg"
+                            className="data-[state=open]:bg-sidebar-accent"
+                            data-test="space-switcher"
+                        >
+                            <div className="flex aspect-square size-8 items-center justify-center rounded-lg bg-sidebar-primary/10 text-sidebar-primary">
+                                {currentSpace.personal ? (
+                                    <User className="size-4" />
+                                ) : (
+                                    <Building2 className="size-4" />
+                                )}
+                            </div>
+                            <div className="grid flex-1 text-left text-sm leading-tight">
+                                <span className="truncate font-medium">
+                                    {currentSpace.name}
+                                </span>
+                                <span className="truncate text-xs text-muted-foreground">
+                                    {currentSpace.personal
+                                        ? __('Personal space')
+                                        : __('Space')}
+                                </span>
+                            </div>
+                            <ChevronsUpDown className="ml-auto size-4" />
+                        </SidebarMenuButton>
+                    </DropdownMenuTrigger>
+                    <DropdownMenuContent
+                        className="w-(--radix-dropdown-menu-trigger-width) min-w-60 rounded-lg"
+                        align="start"
+                        side={
+                            isMobile
+                                ? 'bottom'
+                                : state === 'collapsed'
+                                  ? 'right'
+                                  : 'bottom'
+                        }
+                    >
+                        <DropdownMenuLabel className="text-xs text-muted-foreground">
+                            {__('Spaces')}
+                        </DropdownMenuLabel>
+                        {spaces.map((space) => (
+                            <DropdownMenuItem
+                                key={space.id}
+                                onClick={() => switchTo(space.id)}
+                                className="gap-2"
+                                data-test="space-option"
+                            >
+                                {space.personal ? (
+                                    <User className="size-4 text-muted-foreground" />
+                                ) : (
+                                    <Building2 className="size-4 text-muted-foreground" />
+                                )}
+                                <span className="truncate">{space.name}</span>
+                                {space.id === currentSpace.id && (
+                                    <Check className="ml-auto size-4" />
+                                )}
+                            </DropdownMenuItem>
+                        ))}
+                        <DropdownMenuSeparator />
+                        <DropdownMenuItem
+                            onClick={() => setCreateOpen(true)}
+                            className="gap-2"
+                            data-test="space-create"
+                        >
+                            <Plus className="size-4" />
+                            {__('Create space')}
+                        </DropdownMenuItem>
+                        <DropdownMenuItem asChild className="gap-2">
+                            <Link href={manageSpaces().url}>
+                                <Settings2 className="size-4" />
+                                {__('Manage spaces')}
+                            </Link>
+                        </DropdownMenuItem>
+                    </DropdownMenuContent>
+                </DropdownMenu>
+            </SidebarMenuItem>
+
+            <Dialog open={createOpen} onOpenChange={setCreateOpen}>
+                <DialogContent>
+                    <form onSubmit={createSpace}>
+                        <DialogHeader>
+                            <DialogTitle>{__('Create space')}</DialogTitle>
+                            <DialogDescription>
+                                {__(
+                                    'A space groups its own accounts, transactions, categories and budgets, kept separate from your other spaces.',
+                                )}
+                            </DialogDescription>
+                        </DialogHeader>
+                        <div className="grid gap-2 py-4">
+                            <Label htmlFor="space-name">{__('Name')}</Label>
+                            <Input
+                                id="space-name"
+                                value={name}
+                                onChange={(event) =>
+                                    setName(event.target.value)
+                                }
+                                placeholder={__('e.g. My Company')}
+                                autoFocus
+                                required
+                            />
+                        </div>
+                        <DialogFooter>
+                            <Button
+                                type="button"
+                                variant="outline"
+                                onClick={() => setCreateOpen(false)}
+                            >
+                                {__('Cancel')}
+                            </Button>
+                            <Button
+                                type="submit"
+                                disabled={processing || name.trim() === ''}
+                            >
+                                {__('Create space')}
+                            </Button>
+                        </DialogFooter>
+                    </form>
+                </DialogContent>
+            </Dialog>
+        </SidebarMenu>
+    );
+}
diff --git a/resources/js/contexts/sync-context.tsx b/resources/js/contexts/sync-context.tsx
index cf71e319..2f98bb42 100644
--- a/resources/js/contexts/sync-context.tsx
+++ b/resources/js/contexts/sync-context.tsx
@@ -1,5 +1,6 @@
 import { useOnlineStatus } from '@/hooks/use-online-status';
 import { identifyUser, resetPostHog } from '@/lib/posthog';
+import { transactionSyncService } from '@/services/transaction-sync';
 import type { User } from '@/types/index.d';
 import type { Page } from '@inertiajs/core';
 import { router } from '@inertiajs/react';
@@ -47,16 +48,30 @@ export function SyncProvider({
     const [error, setError] = useState<string | null>(null);
     const [wasOffline, setWasOffline] = useState(!isOnline);
     const lastUserIdRef = useRef<string | null>(null);
+    const lastSpaceIdRef = useRef<string | null>(null);
 
     useEffect(() => {
         const unsubscribe = router.on('navigate', (event) => {
             const page = event.detail.page as Page<{
                 auth?: { user?: User };
+                currentSpace?: { id: string } | null;
             }>;
 
             const user = page.props?.auth?.user ?? null;
             setIsAuthenticated(Boolean(user));
             setCurrentUser(user);
+
+            // The offline cache is a per-space mirror. When the active space
+            // changes (switch or logout), drop it so stale rows from the
+            // previous space never surface and the next sync starts clean.
+            const spaceId = page.props?.currentSpace?.id ?? null;
+            if (
+                lastSpaceIdRef.current !== null &&
+                lastSpaceIdRef.current !== spaceId
+            ) {
+                void transactionSyncService.clearAll();
+            }
+            lastSpaceIdRef.current = spaceId;
         });
 
         return () => {
diff --git a/resources/js/layouts/settings/layout.tsx b/resources/js/layouts/settings/layout.tsx
index 26943f82..f6dab15a 100644
--- a/resources/js/layouts/settings/layout.tsx
+++ b/resources/js/layouts/settings/layout.tsx
@@ -2,6 +2,7 @@ import { index as accountsIndex } from '@/actions/App/Http/Controllers/Settings/
 import { index as automationRulesIndex } from '@/actions/App/Http/Controllers/Settings/AutomationRuleController';
 import { index as categoriesIndex } from '@/actions/App/Http/Controllers/Settings/CategoryController';
 import { index as labelsIndex } from '@/actions/App/Http/Controllers/Settings/LabelController';
+import { index as spacesIndex } from '@/actions/App/Http/Controllers/SpaceController';
 import Heading from '@/components/heading';
 import { Button } from '@/components/ui/button';
 import {
@@ -34,7 +35,18 @@ import { type PropsWithChildren } from 'react';
 const getNavItems = (
     subscriptionsEnabled: boolean,
     isDemoAccount: boolean,
+    spacesEnabled: boolean,
 ): (NavItem | NavSectionHeader | NavDivider)[] => [
+    ...(spacesEnabled
+        ? [
+              {
+                  type: 'nav-item' as const,
+                  title: 'Spaces',
+                  href: spacesIndex(),
+                  icon: null,
+              },
+          ]
+        : []),
     {
         type: 'nav-item' as const,
         title: 'Bank accounts',
@@ -172,7 +184,8 @@ function renderMobileNavGroups(
 }
 
 export default function SettingsLayout({ children }: PropsWithChildren) {
-    const { subscriptionsEnabled, auth } = usePage<SharedData>().props;
+    const { subscriptionsEnabled, auth, features } =
+        usePage<SharedData>().props;
     const isDemoAccount = auth?.isDemoAccount ?? false;
 
     // When server-side rendering, we only render the layout on the client...
@@ -181,7 +194,11 @@ export default function SettingsLayout({ children }: PropsWithChildren) {
     }
 
     const currentPath = window.location.pathname;
-    const sidebarNavItems = getNavItems(subscriptionsEnabled, isDemoAccount);
+    const sidebarNavItems = getNavItems(
+        subscriptionsEnabled,
+        isDemoAccount,
+        features?.spaces ?? false,
+    );
 
     const activeNavItem = sidebarNavItems.find(
         (item): item is NavItem =>
diff --git a/resources/js/pages/dashboard.tsx b/resources/js/pages/dashboard.tsx
index 50942758..a528fe8a 100644
--- a/resources/js/pages/dashboard.tsx
+++ b/resources/js/pages/dashboard.tsx
@@ -311,21 +311,27 @@ export default function Dashboard() {
                         )}
                     </div>
 
-                    <div className="grid gap-4 md:grid-cols-2">
-                        {gridAccounts.map((account) => (
-                            <AccountBalanceCard
-                                key={account.id}
-                                account={account}
-                                onBalanceUpdated={refetch}
-                                linkedLoanMetrics={
-                                    linkedLoanMetricsMap[account.id]
-                                }
-                                displayCurrencyCode={
-                                    netWorthEvolution.currency_code
-                                }
-                            />
-                        ))}
-                    </div>
+                    {gridAccounts.length === 0 ? (
+                        <p className="rounded-lg border border-dashed border-border py-8 text-center text-sm text-muted-foreground">
+                            {__('This space has no accounts yet.')}
+                        </p>
+                    ) : (
+                        <div className="grid gap-4 md:grid-cols-2">
+                            {gridAccounts.map((account) => (
+                                <AccountBalanceCard
+                                    key={account.id}
+                                    account={account}
+                                    onBalanceUpdated={refetch}
+                                    linkedLoanMetrics={
+                                        linkedLoanMetricsMap[account.id]
+                                    }
+                                    displayCurrencyCode={
+                                        netWorthEvolution.currency_code
+                                    }
+                                />
+                            ))}
+                        </div>
+                    )}
 
                     <AccountsManagerDialog
                         open={editOpen}
diff --git a/resources/js/pages/settings/spaces.tsx b/resources/js/pages/settings/spaces.tsx
new file mode 100644
index 00000000..e4d2e748
--- /dev/null
+++ b/resources/js/pages/settings/spaces.tsx
@@ -0,0 +1,315 @@
+import {
+    destroy as destroySpace,
+    select as selectSpace,
+    index as spacesIndex,
+    store as storeSpace,
+    update as updateSpace,
+} from '@/actions/App/Http/Controllers/SpaceController';
+import HeadingSmall from '@/components/heading-small';
+import {
+    AlertDialog,
+    AlertDialogAction,
+    AlertDialogCancel,
+    AlertDialogContent,
+    AlertDialogDescription,
+    AlertDialogFooter,
+    AlertDialogHeader,
+    AlertDialogTitle,
+} from '@/components/ui/alert-dialog';
+import { Button } from '@/components/ui/button';
+import {
+    Dialog,
+    DialogContent,
+    DialogDescription,
+    DialogFooter,
+    DialogHeader,
+    DialogTitle,
+} from '@/components/ui/dialog';
+import { Input } from '@/components/ui/input';
+import { Label } from '@/components/ui/label';
+import AppLayout from '@/layouts/app-layout';
+import SettingsLayout from '@/layouts/settings/layout';
+import { type BreadcrumbItem, type SharedData, type Space } from '@/types';
+import { __ } from '@/utils/i18n';
+import { Head, router, usePage } from '@inertiajs/react';
+import { Building2, Check, User } from 'lucide-react';
+import { FormEvent, useState } from 'react';
+
+const breadcrumbs: BreadcrumbItem[] = [
+    {
+        title: 'Spaces settings',
+        href: spacesIndex().url,
+    },
+];
+
+export default function Spaces() {
+    const { spaces, currentSpace } = usePage<SharedData>().props;
+    const [createOpen, setCreateOpen] = useState(false);
+    const [renaming, setRenaming] = useState<Space | null>(null);
+    const [deleting, setDeleting] = useState<Space | null>(null);
+    const [name, setName] = useState('');
+    const [processing, setProcessing] = useState(false);
+
+    const submitCreate = (event: FormEvent) => {
+        event.preventDefault();
+        setProcessing(true);
+        router.post(
+            storeSpace().url,
+            { name },
+            {
+                preserveScroll: true,
+                onFinish: () => setProcessing(false),
+                onSuccess: () => {
+                    setCreateOpen(false);
+                    setName('');
+                },
+            },
+        );
+    };
+
+    const submitRename = (event: FormEvent) => {
+        event.preventDefault();
+        if (!renaming) {
+            return;
+        }
+        setProcessing(true);
+        router.patch(
+            updateSpace(renaming.id).url,
+            { name },
+            {
+                preserveScroll: true,
+                onFinish: () => setProcessing(false),
+                onSuccess: () => setRenaming(null),
+            },
+        );
+    };
+
+    const confirmDelete = () => {
+        if (!deleting) {
+            return;
+        }
+        setProcessing(true);
+        router.delete(destroySpace(deleting.id).url, {
+            preserveScroll: true,
+            onFinish: () => setProcessing(false),
+            onSuccess: () => setDeleting(null),
+        });
+    };
+
+    return (
+        <AppLayout breadcrumbs={breadcrumbs}>
+            <Head title={__('Spaces')} />
+
+            <SettingsLayout>
+                <div className="space-y-6">
+                    <div className="flex items-start justify-between gap-4">
+                        <HeadingSmall
+                            title={__('Spaces')}
+                            description={__(
+                                'Each space keeps its own accounts, transactions, categories and budgets separate.',
+                            )}
+                        />
+                        <Button onClick={() => setCreateOpen(true)}>
+                            {__('Create space')}
+                        </Button>
+                    </div>
+
+                    <ul className="divide-y divide-border rounded-lg border border-border">
+                        {spaces.map((space) => {
+                            const isCurrent = space.id === currentSpace?.id;
+
+                            return (
+                                <li
+                                    key={space.id}
+                                    className="flex items-center gap-3 px-4 py-3"
+                                    data-test="space-row"
+                                >
+                                    <div className="flex size-9 items-center justify-center rounded-lg bg-muted text-muted-foreground">
+                                        {space.personal ? (
+                                            <User className="size-4" />
+                                        ) : (
+                                            <Building2 className="size-4" />
+                                        )}
+                                    </div>
+                                    <div className="flex-1">
+                                        <div className="flex items-center gap-2 font-medium">
+                                            {space.name}
+                                            {isCurrent && (
+                                                <span className="inline-flex items-center gap-1 rounded-full bg-primary/10 px-2 py-0.5 text-xs text-primary">
+                                                    <Check className="size-3" />
+                                                    {__('Active')}
+                                                </span>
+                                            )}
+                                        </div>
+                                        <div className="text-xs text-muted-foreground">
+                                            {space.personal
+                                                ? __('Personal space')
+                                                : __('Space')}
+                                        </div>
+                                    </div>
+
+                                    <div className="flex items-center gap-2">
+                                        {!isCurrent && (
+                                            <Button
+                                                variant="outline"
+                                                size="sm"
+                                                onClick={() =>
+                                                    router.post(
+                                                        selectSpace(space.id)
+                                                            .url,
+                                                    )
+                                                }
+                                            >
+                                                {__('Switch')}
+                                            </Button>
+                                        )}
+                                        {!space.personal && space.is_owner && (
+                                            <>
+                                                <Button
+                                                    variant="outline"
+                                                    size="sm"
+                                                    onClick={() => {
+                                                        setName(space.name);
+                                                        setRenaming(space);
+                                                    }}
+                                                >
+                                                    {__('Rename')}
+                                                </Button>
+                                                <Button
+                                                    variant="ghost"
+                                                    size="sm"
+                                                    className="text-destructive hover:text-destructive"
+                                                    onClick={() =>
+                                                        setDeleting(space)
+                                                    }
+                                                >
+                                                    {__('Delete')}
+                                                </Button>
+                                            </>
+                                        )}
+                                    </div>
+                                </li>
+                            );
+                        })}
+                    </ul>
+                </div>
+            </SettingsLayout>
+
+            <Dialog open={createOpen} onOpenChange={setCreateOpen}>
+                <DialogContent>
+                    <form onSubmit={submitCreate}>
+                        <DialogHeader>
+                            <DialogTitle>{__('Create space')}</DialogTitle>
+                            <DialogDescription>
+                                {__(
+                                    'A space groups its own accounts, transactions, categories and budgets, kept separate from your other spaces.',
+                                )}
+                            </DialogDescription>
+                        </DialogHeader>
+                        <div className="grid gap-2 py-4">
+                            <Label htmlFor="create-space-name">
+                                {__('Name')}
+                            </Label>
+                            <Input
+                                id="create-space-name"
+                                value={name}
+                                onChange={(event) =>
+                                    setName(event.target.value)
+                                }
+                                placeholder={__('e.g. My Company')}
+                                autoFocus
+                                required
+                            />
+                        </div>
+                        <DialogFooter>
+                            <Button
+                                type="button"
+                                variant="outline"
+                                onClick={() => setCreateOpen(false)}
+                            >
+                                {__('Cancel')}
+                            </Button>
+                            <Button
+                                type="submit"
+                                disabled={processing || name.trim() === ''}
+                            >
+                                {__('Create space')}
+                            </Button>
+                        </DialogFooter>
+                    </form>
+                </DialogContent>
+            </Dialog>
+
+            <Dialog
+                open={renaming !== null}
+                onOpenChange={(open) => !open && setRenaming(null)}
+            >
+                <DialogContent>
+                    <form onSubmit={submitRename}>
+                        <DialogHeader>
+                            <DialogTitle>{__('Rename space')}</DialogTitle>
+                        </DialogHeader>
+                        <div className="grid gap-2 py-4">
+                            <Label htmlFor="rename-space-name">
+                                {__('Name')}
+                            </Label>
+                            <Input
+                                id="rename-space-name"
+                                value={name}
+                                onChange={(event) =>
+                                    setName(event.target.value)
+                                }
+                                autoFocus
+                                required
+                            />
+                        </div>
+                        <DialogFooter>
+                            <Button
+                                type="button"
+                                variant="outline"
+                                onClick={() => setRenaming(null)}
+                            >
+                                {__('Cancel')}
+                            </Button>
+                            <Button
+                                type="submit"
+                                disabled={processing || name.trim() === ''}
+                            >
+                                {__('Save')}
+                            </Button>
+                        </DialogFooter>
+                    </form>
+                </DialogContent>
+            </Dialog>
+
+            <AlertDialog
+                open={deleting !== null}
+                onOpenChange={(open) => !open && setDeleting(null)}
+            >
+                <AlertDialogContent>
+                    <AlertDialogHeader>
+                        <AlertDialogTitle>
+                            {__('Delete space')}
+                        </AlertDialogTitle>
+                        <AlertDialogDescription>
+                            {__('Delete this space? This cannot be undone.')}
+                            {deleting ? ` (${deleting.name})` : ''}
+                        </AlertDialogDescription>
+                    </AlertDialogHeader>
+                    <AlertDialogFooter>
+                        <AlertDialogCancel disabled={processing}>
+                            {__('Cancel')}
+                        </AlertDialogCancel>
+                        <AlertDialogAction
+                            onClick={confirmDelete}
+                            disabled={processing}
+                            variant="destructive"
+                        >
+                            {__('Delete')}
+                        </AlertDialogAction>
+                    </AlertDialogFooter>
+                </AlertDialogContent>
+            </AlertDialog>
+        </AppLayout>
+    );
+}
diff --git a/resources/js/types/index.d.ts b/resources/js/types/index.d.ts
index 3ca7b705..088018e5 100644
--- a/resources/js/types/index.d.ts
+++ b/resources/js/types/index.d.ts
@@ -42,6 +42,14 @@ export interface NavDivider {
 export interface Features {
     cashflow: boolean;
     calculateBalancesOnImport: boolean;
+    spaces: boolean;
+}
+
+export interface Space {
+    id: UUID;
+    name: string;
+    personal: boolean;
+    is_owner: boolean;
 }
 
 export interface ExpiredBankingConnectionNotification {
@@ -82,6 +90,8 @@ export interface SharedData {
     pricing: PricingConfig;
     sidebarOpen: boolean;
     features: Features;
+    currentSpace: Space | null;
+    spaces: Space[];
     expiredBankingConnections: ExpiredBankingConnectionNotification[];
     hasEncryptedAccounts: boolean;
     hasEncryptedTransactions: boolean;
diff --git a/routes/settings.php b/routes/settings.php
index 2071c630..241964b6 100644
--- a/routes/settings.php
+++ b/routes/settings.php
@@ -15,6 +15,7 @@ use App\Http\Controllers\Settings\PasswordController;
 use App\Http\Controllers\Settings\ProfileController;
 use App\Http\Controllers\Settings\TimezoneController;
 use App\Http\Controllers\Settings\TwoFactorAuthenticationController;
+use App\Http\Controllers\SpaceController;
 use App\Http\Controllers\SubscriptionController;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Route;
@@ -60,6 +61,12 @@ Route::middleware('auth')->group(function () {
 
     Route::redirect('settings/budgets', '/budgets')->name('budgets.settings');
 
+    Route::get('settings/spaces', [SpaceController::class, 'index'])->name('spaces.index');
+    Route::post('settings/spaces', [SpaceController::class, 'store'])->name('spaces.store');
+    Route::patch('settings/spaces/{space}', [SpaceController::class, 'update'])->name('spaces.update');
+    Route::delete('settings/spaces/{space}', [SpaceController::class, 'destroy'])->name('spaces.destroy');
+    Route::post('spaces/{space}/switch', [SpaceController::class, 'select'])->name('spaces.switch');
+
     Route::get('settings/automation-rules', [AutomationRuleController::class, 'index'])->name('automation-rules.index');
     Route::post('settings/automation-rules', [AutomationRuleController::class, 'store'])->name('automation-rules.store');
     Route::patch('settings/automation-rules/{automationRule}', [AutomationRuleController::class, 'update'])->name('automation-rules.update');
diff --git a/tests/Feature/InertiaSharedDataTest.php b/tests/Feature/InertiaSharedDataTest.php
index f86c4ec1..71a740df 100644
--- a/tests/Feature/InertiaSharedDataTest.php
+++ b/tests/Feature/InertiaSharedDataTest.php
@@ -99,6 +99,7 @@ test('shared feature flags do not include coinbase flag', function () {
     expect($props['features'])->toBe([
         'cashflow' => true,
         'calculateBalancesOnImport' => false,
+        'spaces' => false,
     ]);
 });
 
diff --git a/tests/Feature/Settings/CategoryTreeTest.php b/tests/Feature/Settings/CategoryTreeTest.php
index 37c3a31d..9bf5ef84 100644
--- a/tests/Feature/Settings/CategoryTreeTest.php
+++ b/tests/Feature/Settings/CategoryTreeTest.php
@@ -210,7 +210,7 @@ test('the tree service expands a parent id to include all descendants', function
     $grandchild = Category::factory()->childOf($child)->create(['user_id' => $user->id]);
     $unrelated = Category::factory()->create(['user_id' => $user->id]);
 
-    $expanded = (new CategoryTree)->expand($user->id, [$root->id]);
+    $expanded = (new CategoryTree)->expand($user->current_space_id, [$root->id]);
 
     expect($expanded)->toContain($root->id, $child->id, $grandchild->id)
         ->not->toContain($unrelated->id);
diff --git a/tests/Feature/Spaces/SpaceFoundationTest.php b/tests/Feature/Spaces/SpaceFoundationTest.php
index c06f5b6a..62d9cd61 100644
--- a/tests/Feature/Spaces/SpaceFoundationTest.php
+++ b/tests/Feature/Spaces/SpaceFoundationTest.php
@@ -1,10 +1,10 @@
 <?php
 
 use App\Actions\CreateDefaultCategories;
+use App\Enums\TransactionSource;
 use App\Models\Account;
 use App\Models\Category;
 use App\Models\Space;
-use App\Models\Transaction;
 use App\Models\User;
 
 it('provisions a personal space when a user is created', function () {
@@ -24,14 +24,20 @@ it('stamps owned rows with the owner\'s current space by default', function () {
     expect($account->space_id)->toBe($user->current_space_id);
 });
 
-it('inherits a transaction\'s space from its account, not the acting user', function () {
+it('inherits a transaction\'s space from its account (the tenant anchor)', function () {
     $owner = User::factory()->create();
     $account = Account::factory()->for($owner)->create();
 
-    // A transaction created with a different acting user still lands in the
-    // account's space (the account is the tenant anchor).
-    $other = User::factory()->create();
-    $transaction = Transaction::factory()->for($account)->create(['user_id' => $other->id]);
+    // Mirrors bank sync: the row is created straight off the account with no
+    // explicit space_id, so the model resolves it from the account.
+    $transaction = $account->transactions()->create([
+        'user_id' => $owner->id,
+        'description' => 'Coffee',
+        'transaction_date' => now(),
+        'amount' => -350,
+        'currency_code' => 'EUR',
+        'source' => TransactionSource::EnableBanking,
+    ]);
 
     expect($transaction->space_id)->toBe($account->space_id);
 });
diff --git a/tests/Feature/Spaces/SpaceManagementTest.php b/tests/Feature/Spaces/SpaceManagementTest.php
new file mode 100644
index 00000000..b9749fd3
--- /dev/null
+++ b/tests/Feature/Spaces/SpaceManagementTest.php
@@ -0,0 +1,99 @@
+<?php
+
+use App\Actions\CreateDefaultCategories;
+use App\Features\Spaces;
+use App\Models\Account;
+use App\Models\Category;
+use App\Models\Space;
+use App\Models\User;
+use Laravel\Pennant\Feature;
+
+it('creates a space, seeds its categories and switches to it', function () {
+    $user = User::factory()->onboarded()->create();
+    Feature::for($user)->activate(Spaces::class);
+
+    // The personal space already carries the default categories (as it would
+    // after registration), so seeding the same names into a second space must
+    // NOT collide — category name uniqueness is per space, not per user.
+    app(CreateDefaultCategories::class)->handle($user, $user->personalSpace);
+
+    $this->actingAs($user)->post('/settings/spaces', ['name' => 'Acme'])
+        ->assertRedirect();
+
+    $space = Space::query()->where('owner_id', $user->id)->where('personal', false)->first();
+
+    expect($space)->not->toBeNull()
+        ->and($user->fresh()->current_space_id)->toBe($space->id)
+        ->and(Category::where('space_id', $space->id)->count())->toBeGreaterThan(0)
+        ->and(Category::where('space_id', $user->personalSpace->id)->count())->toBeGreaterThan(0);
+});
+
+it('forbids creating a space without the spaces feature', function () {
+    $user = User::factory()->onboarded()->create();
+
+    $this->actingAs($user)->post('/settings/spaces', ['name' => 'Acme'])
+        ->assertForbidden();
+});
+
+it('lets the owner rename a non-personal space', function () {
+    $user = User::factory()->onboarded()->create();
+    Feature::for($user)->activate(Spaces::class);
+    $space = $user->ownedSpaces()->create(['name' => 'Old', 'personal' => false]);
+
+    $this->actingAs($user)->patch("/settings/spaces/{$space->id}", ['name' => 'New'])
+        ->assertRedirect();
+
+    expect($space->fresh()->name)->toBe('New');
+});
+
+it('never lets the personal space be renamed or deleted', function () {
+    $user = User::factory()->onboarded()->create();
+    Feature::for($user)->activate(Spaces::class);
+    $personal = $user->personalSpace;
+
+    $this->actingAs($user)->patch("/settings/spaces/{$personal->id}", ['name' => 'Nope'])
+        ->assertForbidden();
+
+    $this->actingAs($user)->delete("/settings/spaces/{$personal->id}")
+        ->assertForbidden();
+});
+
+it('refuses to delete a space that still has accounts', function () {
+    $user = User::factory()->onboarded()->create();
+    Feature::for($user)->activate(Spaces::class);
+    $space = $user->ownedSpaces()->create(['name' => 'Acme', 'personal' => false]);
+    Account::factory()->for($user)->create(['space_id' => $space->id]);
+
+    $this->actingAs($user)->delete("/settings/spaces/{$space->id}")
+        ->assertSessionHas('error');
+
+    expect($space->fresh())->not->toBeNull();
+});
+
+it('deletes an empty space and falls back to the personal space', function () {
+    $user = User::factory()->onboarded()->create();
+    Feature::for($user)->activate(Spaces::class);
+    $space = $user->ownedSpaces()->create(['name' => 'Acme', 'personal' => false]);
+    $user->forceFill(['current_space_id' => $space->id])->save();
+
+    $this->actingAs($user)->delete("/settings/spaces/{$space->id}")
+        ->assertRedirect();
+
+    expect(Space::find($space->id))->toBeNull()
+        ->and($user->fresh()->current_space_id)->toBe($user->personalSpace->id);
+});
+
+it('switches the active space and rejects spaces the user cannot access', function () {
+    $user = User::factory()->onboarded()->create();
+    $space = $user->ownedSpaces()->create(['name' => 'Acme', 'personal' => false]);
+
+    $this->actingAs($user)->post("/spaces/{$space->id}/switch")
+        ->assertRedirect();
+    expect($user->fresh()->current_space_id)->toBe($space->id);
+
+    $stranger = User::factory()->create();
+    $strangerSpace = $stranger->personalSpace;
+
+    $this->actingAs($user)->post("/spaces/{$strangerSpace->id}/switch")
+        ->assertForbidden();
+});
diff --git a/tests/Feature/Spaces/SpaceScopingTest.php b/tests/Feature/Spaces/SpaceScopingTest.php
new file mode 100644
index 00000000..ca16fdf6
--- /dev/null
+++ b/tests/Feature/Spaces/SpaceScopingTest.php
@@ -0,0 +1,109 @@
+<?php
+
+use App\Features\Spaces;
+use App\Models\Account;
+use App\Models\Category;
+use App\Models\Space;
+use App\Models\Transaction;
+use App\Models\User;
+use Inertia\Testing\AssertableInertia;
+use Laravel\Pennant\Feature;
+
+/**
+ * A user with two spaces must only ever see the active space's data. These are
+ * the anti-leak guardrails for the whole multi-tenant feature.
+ */
+function userWithTwoSpaces(): array
+{
+    $user = User::factory()->onboarded()->create();
+    $personal = $user->personalSpace;
+    $business = $user->ownedSpaces()->create(['name' => 'Acme', 'personal' => false]);
+
+    return [$user, $personal, $business];
+}
+
+it('only lists the active space accounts', function () {
+    [$user, $personal, $business] = userWithTwoSpaces();
+
+    Account::factory()->for($user)->create(['space_id' => $personal->id, 'name' => 'Personal Checking']);
+    Account::factory()->for($user)->create(['space_id' => $business->id, 'name' => 'Acme Payroll']);
+
+    $user->forceFill(['current_space_id' => $business->id])->save();
+
+    $this->actingAs($user)->get('/accounts')
+        ->assertInertia(fn (AssertableInertia $page) => $page
+            ->component('Accounts/Index')
+            ->has('accounts', 1)
+            ->where('accounts.0.name', 'Acme Payroll'));
+
+    $user->forceFill(['current_space_id' => $personal->id])->save();
+
+    $this->actingAs($user)->get('/accounts')
+        ->assertInertia(fn (AssertableInertia $page) => $page
+            ->has('accounts', 1)
+            ->where('accounts.0.name', 'Personal Checking'));
+});
+
+it('only syncs the active space transactions', function () {
+    [$user, $personal, $business] = userWithTwoSpaces();
+
+    $personalAccount = Account::factory()->for($user)->create(['space_id' => $personal->id]);
+    $businessAccount = Account::factory()->for($user)->create(['space_id' => $business->id]);
+
+    Transaction::factory()->for($personalAccount)->create(['user_id' => $user->id]);
+    $businessTx = Transaction::factory()->for($businessAccount)->create(['user_id' => $user->id]);
+
+    $user->forceFill(['current_space_id' => $business->id])->save();
+
+    $response = $this->actingAs($user)->getJson('/api/sync/transactions');
+    $response->assertOk();
+
+    $ids = collect($response->json('data'))->pluck('id');
+    expect($ids)->toContain($businessTx->id)
+        ->and($ids)->toHaveCount(1);
+});
+
+it('scopes categories on the settings page to the active space', function () {
+    [$user, $personal, $business] = userWithTwoSpaces();
+
+    Category::factory()->for($user)->create(['space_id' => $personal->id, 'name' => 'Personal Only']);
+    Category::factory()->for($user)->create(['space_id' => $business->id, 'name' => 'Business Only']);
+
+    $user->forceFill(['current_space_id' => $business->id])->save();
+
+    $this->actingAs($user)->get('/settings/categories')
+        ->assertInertia(fn (AssertableInertia $page) => $page
+            ->has('categories', 1)
+            ->where('categories.0.name', 'Business Only'));
+});
+
+it('cannot update a transaction that lives in another space', function () {
+    [$user, $personal, $business] = userWithTwoSpaces();
+
+    // A transaction created by someone else in a space this user cannot access.
+    $stranger = User::factory()->create();
+    $strangerAccount = Account::factory()->for($stranger)->create();
+    $strangerSpace = $stranger->personalSpace;
+    $foreignTx = Transaction::factory()->for($strangerAccount)->create([
+        'user_id' => $stranger->id,
+        'space_id' => $strangerSpace->id,
+    ]);
+
+    $this->actingAs($user)
+        ->patchJson("/transactions/{$foreignTx->id}", ['description' => 'hacked'])
+        ->assertForbidden();
+});
+
+it('exposes the accessible spaces and current space as shared props', function () {
+    [$user, $personal, $business] = userWithTwoSpaces();
+    Feature::for($user)->activate(Spaces::class);
+
+    $user->forceFill(['current_space_id' => $business->id])->save();
+
+    $this->actingAs($user)->get('/accounts')
+        ->assertInertia(fn (AssertableInertia $page) => $page
+            ->where('currentSpace.id', $business->id)
+            ->where('currentSpace.name', 'Acme')
+            ->where('features.spaces', true)
+            ->has('spaces', 2));
+});
diff --git a/tests/Performance/PageQueryCountTest.php b/tests/Performance/PageQueryCountTest.php
index abc16d39..127072e1 100644
--- a/tests/Performance/PageQueryCountTest.php
+++ b/tests/Performance/PageQueryCountTest.php
@@ -33,13 +33,13 @@ beforeEach(function () {
 // ──────────────────────────────────────────────────────────────────────────
 
 test('dashboard page does not exceed query threshold', function () {
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('dashboard'))->assertOk();
     }, 'Dashboard');
 });
 
 test('accounts index page does not exceed query threshold', function () {
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('accounts.list'))->assertOk();
     }, 'Accounts Index');
 });
@@ -51,19 +51,19 @@ test('account show page does not exceed query threshold', function () {
         'type' => AccountType::Checking,
     ]);
 
-    assertMaxQueries(18, function () use ($account) {
+    assertMaxQueries(20, function () use ($account) {
         $this->get(route('accounts.show', $account))->assertOk();
     }, 'Account Show');
 });
 
 test('transactions index page does not exceed query threshold', function () {
-    assertMaxQueries(21, function () {
+    assertMaxQueries(23, function () {
         $this->get(route('transactions.index'))->assertOk();
     }, 'Transactions Index');
 });
 
 test('budgets index page does not exceed query threshold', function () {
-    assertMaxQueries(21, function () {
+    assertMaxQueries(23, function () {
         $this->get(route('budgets.index'))->assertOk();
     }, 'Budgets Index');
 });
@@ -71,13 +71,13 @@ test('budgets index page does not exceed query threshold', function () {
 test('budget show page does not exceed query threshold', function () {
     $budget = $this->user->budgets()->first();
 
-    assertMaxQueries(22, function () use ($budget) {
+    assertMaxQueries(24, function () use ($budget) {
         $this->get(route('budgets.show', $budget))->assertOk();
     }, 'Budget Show');
 });
 
 test('cashflow page does not exceed query threshold', function () {
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('cashflow'))->assertOk();
     }, 'Cashflow');
 });
@@ -87,37 +87,37 @@ test('cashflow page does not exceed query threshold', function () {
 // ──────────────────────────────────────────────────────────────────────────
 
 test('settings accounts page does not exceed query threshold', function () {
-    assertMaxQueries(17, function () {
+    assertMaxQueries(19, function () {
         $this->get(route('accounts.index'))->assertOk();
     }, 'Settings Accounts');
 });
 
 test('settings categories page does not exceed query threshold', function () {
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('categories.index'))->assertOk();
     }, 'Settings Categories');
 });
 
 test('settings labels page does not exceed query threshold', function () {
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('labels.index'))->assertOk();
     }, 'Settings Labels');
 });
 
 test('settings automation rules page does not exceed query threshold', function () {
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('automation-rules.index'))->assertOk();
     }, 'Settings Automation Rules');
 });
 
 test('settings account/profile page does not exceed query threshold', function () {
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('account.edit'))->assertOk();
     }, 'Settings Account/Profile');
 });
 
 test('settings appearance page does not exceed query threshold', function () {
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('appearance.edit'))->assertOk();
     }, 'Settings Appearance');
 });
@@ -147,7 +147,7 @@ test('dashboard query count does not scale with number of accounts', function ()
     }
 
     // Same threshold as 3 accounts — query count must not grow with data
-    assertMaxQueries(15, function () {
+    assertMaxQueries(17, function () {
         $this->get(route('dashboard'))->assertOk();
     }, 'Dashboard with 10 accounts');
 });
@@ -164,7 +164,7 @@ test('transactions page query count does not scale with number of transactions',
     ]);
 
     // Same threshold — paginated queries should not scale
-    assertMaxQueries(21, function () {
+    assertMaxQueries(23, function () {
         $this->get(route('transactions.index'))->assertOk();
     }, 'Transactions with 120 records');
 });