Errors - Inboundr

Inboundr uses conventional HTTP status codes and always returns an error field on failures.

Status codes

Code	Meaning
`200 OK`	Request succeeded.
`201 Created`	Resource created (create domain/address/endpoint).
`204 No Content`	Succeeded with no body (delete).
`400 Bad Request`	Validation failed — check the `error` field.
`401 Unauthorized`	Missing/invalid API key.
`403 Forbidden`	Read-only key attempting a write.
`402 Payment Required`	Plan allotment reached (Free plan). See Billing.
`404 Not Found`	Resource doesn’t exist or isn’t yours.
`409 Conflict`	Already exists (e.g. domain already registered).
`429 Too Many Requests`	Over the rate limit.
`503 Service Unavailable`	A dependency (e.g. attachment storage) isn’t configured.

Error shape

Most errors return a simple message:

{ "error": "Email not found" }

Validation errors (400) return a structured tree describing which fields failed, so you can surface field-level messages:

{
  "error": {
    "errors": [],
    "properties": {
      "localPart": { "errors": ["Invalid local part"] },
      "domainId": { "errors": ["Required"] }
    }
  }
}

For 429, honour the Retry-After header. For 402, you’ve reached your monthly allotment: either upgrade your plan, or turn on pay-as-you-go to keep going and be billed for the overage.