Errors & Rate Limits

HTTP status codes

Code	Meaning
200	Success.
400	Bad request — check the request body or parameters.
401	Unauthorized — missing or invalid API key/token.
403	Forbidden — key lacks the required scope or the account is not active.
404	Resource not found.
409	Conflict — the resource already exists or is in the wrong state.
422	Validation error — the response detail lists the issues.
429	Rate limit exceeded.
500	Server error — retry with backoff.

Error format

Most errors return a simple detail message:

{
  "detail": "Domain not verified"
}

Validation errors may return an array of Pydantic-style errors:

{
  "detail": [
    {"loc": ["body", "from_email"], "msg": "invalid email address", "type": "value_error"}
  ]
}

Rate-limited requests return:

{
  "code": "RATE_LIMIT_EXCEEDED",
  "message": "Rate limit exceeded. Please slow down.",
  "retry_after": 60
}

Rate limits

Limits depend on the endpoint and your account configuration. If the API returns 429, wait for the duration in Retry-After before trying again. Queue send requests and use exponential backoff instead of retrying in a tight loop.