Error codes
HTTP status codes returned by the MailSentry API and what to do about each one.
Status codes
| Status | Meaning | What to do |
|---|---|---|
200 | Success | Request completed. Parse the response body. |
400 | Bad request | Missing or invalid email field. Check your request body. |
401 | Unauthorized | Missing or invalid API key. Check the X-API-Key header. |
402 | Payment required | Monthly limit reached. Upgrade your plan or wait until next month. |
429 | Too many requests | Rate limit exceeded. Wait and retry with backoff. See Rate limits. |
500 | Server error | Something went wrong on our end. Retry after a short delay. If persistent, check system status. |
Error response format
Error responses include a JSON body with a message:
{
"error": "Monthly check limit reached",
"status": 402
}The error field is always a human-readable string you can log or display.