HTTP Status Code Lookup
Search common HTTP response codes with plain-English explanations and debugging tips. Useful for API testing, browser issues, and server monitoring.
Why This Tool Is Useful
When an endpoint fails, the status code is your first clue. A 401 means auth problems, 404 means missing route/resource, and 500 means server-side failure. If you are validating webhook or API payloads, this pairs well with our JSON Formatter.
Quick Debugging Guide by Status Family
- 2xx: Request succeeded. Investigate response body content if behavior still looks wrong.
- 3xx: Redirects in effect. Confirm canonical URLs and redirect loops.
- 4xx: Client-side request issue. Re-check auth headers, payload format, and endpoint path.
- 5xx: Server-side issue. Review logs, upstream health, and timeout settings.
Most Searched Error Codes
In day-to-day operations, teams most often search for 401, 403, 404, 429, 500, 502, and 504. Keeping a fast lookup page for these codes can cut incident triage time and reduce guesswork.
FAQ
Is this list exhaustive?
It focuses on the most commonly encountered status codes in production web apps and APIs.
What should I check after a 429?
Review rate limits, retry-after headers, request bursts, and background job pacing.
Why do I get 200 but still see an app error?
A successful transport status can still include business-logic errors inside the response body. Check payload fields and application-level error flags.
How do I investigate recurring 5xx spikes?
Correlate server logs, deployment changes, and dependency latency around the same timestamp windows.
