Response Envelope & Error Format

Every API response is wrapped consistently, whether it succeeds or fails.

Success

{
  "data": { "...": "..." }
}

The actual resource or list is always under a top-level data key — never returned bare.

Error

{
  "message": "A human-readable description of what went wrong"
}

Errors are distinguished by HTTP status code, not by a field in the body:

Status	Meaning
400	Malformed request (bad input, failed validation)
401	Missing or invalid API key
403	The key's scopes don't cover this operation
404	The resource doesn't exist, or isn't visible to your organization
409	The request conflicts with existing state
422	The request is well-formed but violates a policy (e.g. the impersonation blocklist)
429	Rate limited — see Rate Limits
503	The deployment isn't configured to serve this request (e.g. no inbox domains configured)