HTTP Status Code Lookup
Search any HTTP status code or keyword for its meaning and causes. Free to use, no signup required for occasional use.
Request succeeded.
Common causes: Standard successful response.
Resource was successfully created.
Common causes: Typical response to a POST that creates a resource.
Success, but no body to return.
Common causes: Common for DELETE or PUT with no response payload.
Resource permanently moved to a new URL.
Common causes: Redirects, domain changes.
Resource temporarily at a different URL.
Common causes: Temporary redirects, login flows.
Cached version is still valid.
Common causes: Conditional GET with matching ETag/If-Modified-Since.
Server could not understand the request.
Common causes: Malformed JSON, missing required fields, invalid params.
Authentication is required or failed.
Common causes: Missing/invalid/expired auth token.
Authenticated but not allowed to access.
Common causes: Insufficient permissions, blocked IP, CORS policy.
Resource doesn't exist at this URL.
Common causes: Typo in URL, deleted resource, wrong route.
HTTP method not supported for this route.
Common causes: Calling POST on a GET-only endpoint, etc.
Server timed out waiting for the request.
Common causes: Slow client, network issues.
Request conflicts with current state.
Common causes: Duplicate resource creation, edit conflicts.
Well-formed request but semantically invalid.
Common causes: Validation errors on otherwise valid JSON.
Rate limit exceeded.
Common causes: Client sending requests faster than the API allows.
Generic server-side failure.
Common causes: Unhandled exceptions, bugs, misconfiguration.
Upstream server returned an invalid response.
Common causes: Proxy/load balancer issues, crashed backend.
Server temporarily unable to handle requests.
Common causes: Overload, maintenance, deploys.
Upstream server took too long to respond.
Common causes: Slow backend, network partition.
What is the HTTP Status Code Lookup?
The HTTP Status Code Lookup is a searchable reference covering the status codes developers run into most often — from 200 OK through redirects, client errors like 404 and 429, and server errors like 500 and 503. Rather than searching the web for what a specific code means every time it shows up in a log or API response, you can type the code or a keyword and instantly see its meaning along with common causes, which speeds up debugging failed requests.
How to use it
Type a status code (e.g. 404) or a keyword (e.g. 'rate limit' or 'timeout') into the search box, and matching entries appear immediately with their meaning and typical causes.
Frequently asked questions
Does it cover every HTTP status code?
It covers the most commonly encountered codes across 2xx, 3xx, 4xx, and 5xx ranges, focused on the ones developers see day to day.
Can I search by keyword instead of the number?
Yes, searching terms like 'not found' or 'unauthorized' will match relevant status codes.
Is this reference kept up to date with HTTP standards?
It reflects the standard, widely-used meanings defined in HTTP specifications.