## What
Adds **Interactive Brokers** as a banking sync provider (investment
account, balances only), mirroring the Indexa Capital integration.
It uses the **Flex Web Service** rather than IBKR's Web API: the Web API
requires registering as an IBKR third party (business entity, Compliance
approval, RSA-signed OAuth, ~3-5 weeks), which is overkill for read-only
balance sync. Flex is a read-only token + Query ID model that fits our
existing API-key provider shape.
### How the sync works
- The user creates an Activity Flex Query (NAV + Open Positions) and a
Flex Web Service token in their IBKR Client Portal, then pastes both.
- Client flow: `SendRequest` → reference code → poll `GetStatement` →
parse the XML statement.
- Mapping: `EquitySummaryByReportDateInBase@total` → `balance` (daily
rows give historical backfill on first sync); `Σ(OpenPosition
costBasisMoney × fxRateToBase) + cash` → `invested_amount`, so **profit
derives as `balance − invested_amount`** (unrealized P&L), like Indexa
Capital. Everything is already in base currency, so no FX conversion is
needed.
- One statement covers every account, so the syncer fetches once per
connection to respect IB's per-query rate limit.
- IB returns HTTP 200 with an error XML, so the client translates Flex
error codes into the exceptions the sync job already understands:
`RequestException(401)` for token problems, `RequestException(429)` for
throttling, `TransientBankingProviderException` otherwise.
### Connect flow
- New connect/update-credentials endpoints validate the credentials by
pulling a statement, then build pending accounts from it.
- Credentials reuse the encrypted `api_token` (Flex token) and
`api_secret` (Flex Query ID) columns — **no migration**.
- The IB option (two fields) is added to the connect dialog, inline
connect flow, and update-credentials dialog, with Spanish translations.
## Feature flag (why this is a draft)
Gated behind a Pennant feature `App\Features\InteractiveBrokers` (off by
default). It was built against documented/open-source Flex XML fixtures,
**not a live IBKR account** (we don't have one). Before enabling,
validate against a real account (beta tester or a free IBKR account):
```
php artisan feature:enable InteractiveBrokers user@example.com
```
If the parser needs tweaks against real XML, they should be minor
(field-name level).
## Tests
- Client + balance sync: NAV → balance, invested/profit, daily backfill,
since-date incremental, multi-account, GetStatement polling, token-401 /
rate-limit-429 mapping.
- Controller: feature-flag gate (403), valid/invalid credentials,
subscription gate, onboarding auto-create, validation.
- Factory wiring, enum cases, job-level sync, feature-flag visibility
(vitest).
- Spanish translations added (enforced by `LocalizationTest`).
All green: `pint --test`, `phpstan`, OpenBanking + localization suite,
vitest.
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