Errors

Errors arrive in the standard envelope with a machine-readable error.code. Switch on the code, not the message.

Standard codes

Code	HTTP	When
`invalid_request`	400	Validation failure — missing field, wrong type, out-of-range
`invalid_json`	400	Body wasn't parseable JSON
`unauthorized`	401	Missing or invalid `Authorization` header
`forbidden`	403	Authenticated, but this credential can't perform the action
`account_not_active`	403	The account's state forbids it
`account_trade_frozen`	403	Account is `trade_frozen`
`not_found`	404	Resource doesn't exist (or belongs to another account)
`instrument_halted`	409	Instrument is not in trading state
`stp_aborted`	409	Self-trade prevention blocked the order
`payload_too_large`	413	Body exceeded the 64 KiB cap
`insufficient_funds`	422	Available collateral can't cover the order's hold
`fok_would_not_fully_fill`	422	FOK order can't fill in full against the current book
`max_cost_blocks_any_fill`	422	Market BUY whose `max_cost` blocks all offered liquidity
`market_no_liquidity`	422	Market order has no counterparty
`internal_error`	500	Unexpected server-side failure — report the `correlation_id`
`service_unavailable`	503	A required downstream is unreachable — retry with backoff
`engine_timeout`	504	Engine didn't ack within the deadline — treat outcome as unknown

Parameter-parse failures use specific codes of the form invalid_order_id, invalid_instrument_id, invalid_credential_id, invalid_resolution.

400/401/403/404/409/413/422 — deterministic; retrying the same request will fail the same way. Fix the request.
503 — retry with exponential backoff and jitter.
504 (engine_timeout) — the outcome is unknown: the order may or may not have been accepted. Reconcile via GET /v1/orders before re-placing; blind retries can double-place.

Operation-specific reject reasons (order rejects, cancel rejects) are documented on each endpoint's reference page.