Flow Unified API

Errors

Structured JSON errors — 4xx for request/access problems, 5xx for retryable platform failures.

Errors are returned as structured JSON. Treat 4xx as request or access problems, and 5xx as retryable platform failures.

StatusMeaning
400Invalid request — malformed body, missing mappingKey, or a body that fails the entity's unified schema validation.
401Missing or expired bearer token. Generate a fresh token and retry.
404Unknown accountId, entityType, or a mappingKey that isn't configured for this entity.
429The backing system's rate limit was reached. Retry with exponential backoff.
5xxTemporary Flow or platform issue. Safe to retry idempotent reads; retry writes with the same externalId — it doubles as the idempotency key.