Errors

Errors are a JSON object with a stable string code, a message, and a request id:

{ "error": { "code": "PRICE_BAND_EXCEEDED", "message": "…" },
  "request_id": "req_…" }

Localize by code. HTTP status follows REST conventions (400 bad body, 401 auth, 404 not found, 409 conflict, 422 business-rule rejection, 429 rate limit).

vs. Alpaca: Alpaca uses numeric codes (40310000). Boursa uses readable string codes.

Auth

Code	Meaning
UNAUTHENTICATED	missing/invalid key
SIGNATURE_INVALID	bad HMAC signature
SIGNATURE_EXPIRED	timestamp outside ±300s
SIGNATURE_REQUIRED	signature missing on a money endpoint
IDEMPOTENCY_KEY_REQUIRED	missing on a state change
RATE_LIMITED	slow down

Orders

Code	Meaning
MARKET_CLOSED	session closed (and not queueable)
INSTRUMENT_HALTED / INSTRUMENT_UNKNOWN	instrument state
TICK_VIOLATION	price not a tick multiple
PRICE_BAND_EXCEEDED	price outside ±20%
INSUFFICIENT_SETTLED_CASH / INSUFFICIENT_SETTLED_SECURITIES	balance
SUITABILITY_REQUIRED / RISK_ACK_REQUIRED	gating
INVESTOR_RESTRICTED / SHARIAH_RESTRICTED	account/screen
INVALID_TIME_IN_FORCE	bad TIF
CLIENT_ORDER_ID_EXISTS	reused client_order_id
ORDER_NOT_CANCELLABLE	already terminal

Funding

Code	Meaning
RAIL_LIMIT_EXCEEDED	over the per-transfer/day limit
RAIL_FAILED / RAIL_SUBMIT_FAILED	payment-rail failure
INVALID_AMOUNT / INVALID_DIRECTION	bad input

KYC

Code	Meaning
DOCUMENTS_REQUIRED	both ID sides needed
IMAGE_TOO_LARGE / IMAGE_FORMAT_UNSUPPORTED	upload validation
SCREENING_REJECTED	broker declined
APPLICATION_NOT_EDITABLE	wrong state