Errors

Every error response uses one envelope:

{
  "error": {
    "code": "<machine_code>",
    "message": "<human text>"
  }
}

code is a machine-readable snake_case string. Branch on this, not the HTTP status alone.
message is a human-readable English string for logs and developer display.

Each operation page lists the exact code values that operation emits.

Status codes

Status	Meaning
`400`	The request body or query failed validation.
`401`	No valid credential was presented.
`403`	The credential is valid but does not permit this action.
`404`	The resource does not exist or is not visible to the caller.
`409`	The request conflicts with the resource's current state.
`429`	Rate limit exceeded.
`500`	The server failed to complete the request.

These appear across many operations:

Code	Status	Meaning
`invalid_body`	`400`	Request body failed validation.
`invalid_input`	`400`	A field failed validation.
`unauthorized`	`401`	Authentication required.
`insufficient_scope`	`403`	The API key lacks the required scope.
`not_found`	`404`	Resource not found or not visible.
`already_revoked`	`409`	The target resource is already revoked.
`rate_limit_exceeded`	`429`	Too many requests; see `Retry-After`.
`internal_error`	`500`	Unexpected server error.

A 429 carries three headers:

Back off until Retry-After elapses, then retry the same request.