Errors

OpenSend returns JSON errors. Public API errors may include stable fields such as name, code, message, and statusCode.

Common errors

• missing_api_key — no Bearer token was provided.
• invalid_api_key — token was not recognized.
• validation_error — request body failed validation.
• rate_limit_exceeded — retry after the returned window.
• recipient_suppressed — recipient cannot be sent to because of suppression policy.
• idempotency_conflict — the same idempotency key was reused for a different payload inside the replay window.

Treat error names as programmatic identifiers and error messages as human-facing context.