Free tool · 🚦 HTTP status codes reference
Every status code,with the fix.
502 from NGINX, 429 from an API, 308 vs 301 for SEO — search the code or the symptom and get the meaning, likely cause and fix in one card.
Based on RFC 9110 plus common server-specific codes (NGINX 499, Cloudflare 52x).
What it checks
Everything we would look at first on a client call.
Free, no sign-up, no email gate. If the report shows red, the fix is written next to it — and we are one click away if you would rather we did it.
- All standard codes with meaning, cause and fix
- SEO notes on redirects and errors
- Server-specific codes (NGINX, Cloudflare)
- Search by code or symptom
FAQ
Common questions
301 or 308?
Both are permanent. 308 preserves the HTTP method (POST stays POST); 301 may become GET. For page moves, 301 is universally understood.
502 vs 503 vs 504?
502: the upstream returned garbage or refused. 503: the server is overloaded or in maintenance. 504: the upstream took too long.