HTTP Status Codes Glossary

Understand every HTTP status code and its monitoring impact.

HTTP status codes are the universal language of the web. They indicate whether a request succeeded, failed, or requires additional action. Understanding these codes is essential for troubleshooting.

This glossary covers the most common codes, organized by category. Each code includes its meaning and implications for monitoring.

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Frequently Asked Questions

Does a 200 code guarantee everything works?

No. A server can return 200 with an application error page. Use content verification.

How to differentiate 401 and 403?

401 = not authenticated (who are you?). 403 = authenticated but not authorized (you don't have permission).

Is 304 code a problem?

No, it's normal and desirable. It indicates caching is working correctly.

Why are 5xx codes more serious than 4xx?

4xx are client errors (bad request). 5xx indicate your server has a problem.

How to diagnose a 502 Bad Gateway?

Check that the upstream server is reachable, that timeouts are sufficient, and check proxy logs.

Is a 503 during maintenance normal?

Yes, it's even best practice. 503 indicates temporary and intentional unavailability.

Master HTTP Codes

Understanding HTTP codes is fundamental to quickly diagnosing problems. This glossary is your quick reference.

MoniTao monitors your services' response codes and alerts you when an unexpected code appears. Configure your monitors for complete coverage.

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