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.
seo.glossaire_http.cat_1xx_title
seo.glossaire_http.cat_1xx_desc
- 100 Continue - 100 Continue
- 101 Switching Protocols - 101 Switching Protocols
seo.glossaire_http.cat_2xx_title
seo.glossaire_http.cat_2xx_desc
- 200 OK - 200 OK
- 201 Created - 201 Created
- 204 No Content - 204 No Content
seo.glossaire_http.cat_3xx_title
seo.glossaire_http.cat_3xx_desc
- 301 Moved Permanently - 301 Moved Permanently
- 302 Found - 302 Found
- 304 Not Modified - 304 Not Modified
seo.glossaire_http.cat_4xx_title
seo.glossaire_http.cat_4xx_desc
- 400 Bad Request - 400 Bad Request
- 401 Unauthorized - 401 Unauthorized
- 403 Forbidden - 403 Forbidden
- 404 Not Found - 404 Not Found
- 429 Too Many Requests - 429 Too Many Requests
seo.glossaire_http.cat_5xx_title
seo.glossaire_http.cat_5xx_desc
- 500 Internal Server Error - 500 Internal Server Error
- 502 Bad Gateway - 502 Bad Gateway
- 503 Service Unavailable - 503 Service Unavailable
- 504 Gateway Timeout - 504 Gateway Timeout
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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