HTTP Status Code Reference
Search and browse every HTTP status code with common causes
The server has received the request headers and the client should proceed to send the request body.
The requester has asked the server to switch protocols and the server has agreed to do so.
WebDAV: The server has received and is processing the request, but no response is available yet.
Used to return some response headers before the final HTTP message.
The request succeeded. Response depends on method: GET returns the resource, POST returns result of the action.
The request succeeded and a new resource was created. Typically the response for POST requests.
The request has been received but not yet acted upon. Common in async / batch processing.
The request succeeded but no content is returned. Common for DELETE and PUT responses.
Used to deliver a range of a resource — for resumable downloads and video streaming.
The resource has been moved permanently to a new URL. Search engines will update indexes.
The resource is temporarily at a different URL. Original URL should still be used for future requests.
The cached version is still valid. Used with If-Modified-Since or ETag headers.
Like 302, but the method (POST/PUT) must not change on redirect.
Like 301, but the method must not change on redirect.
The server can't process the request due to a client error (malformed syntax, invalid JSON, missing fields).
Authentication is required and has failed or not been provided. Send an Authorization header.
Reserved for future use. Sometimes used by APIs to indicate quota / billing issues.
The server understood the request but refuses to authorize it. Different from 401 — auth won't help.
The server can't find the requested resource. Check the URL and route definitions.
The HTTP method is not supported for this resource. Check the Allow response header.
The server timed out waiting for the request. Client may retry without modifications.
The request conflicts with current state — commonly a version conflict or duplicate resource.
The resource is permanently gone. Stronger than 404 — signals the removal is intentional.
The request body exceeds the server's size limit. Check nginx/gateway client_max_body_size.
The Content-Type isn't supported. Check the Content-Type header.
An April Fools' joke from RFC 2324. Occasionally used as a placeholder or easter egg.
The request is well-formed but semantically invalid. Very common in JSON APIs for validation errors.
Rate limit exceeded. Check the Retry-After header for how long to wait.
A generic error indicating something went wrong on the server. Check server logs.
The server doesn't support the functionality required to fulfill the request.
The server, acting as a gateway, received an invalid response from an upstream server.
The server is not ready to handle the request — commonly during maintenance or overload.
The server, acting as a gateway, did not get a response in time from the upstream server.
The server does not support the HTTP protocol version used in the request.
How it works
- 1Type a code or keyword
Try '429' for rate limits, 'auth' for authorization codes, or 'gateway' for upstream errors.
- 2Read the description
Each entry explains what the code means and the common causes in real APIs.
- 3Bookmark for later
The list is fully static — a fast reference next to your terminal.
About HTTP Status Code Reference
Free HTTP status code lookup. Search by number (404), name (Unauthorized), or keyword (rate limit) to see every 1xx–5xx status code, what it means, and common causes. A quick reference for API debugging and web development. HTTP Status Code Reference on 712 Tools runs entirely inside your browser using modern JavaScript APIs — no server ever sees your data. That means instant results, complete privacy, and no upload limits.
Whether you need to search and browse every http status code with common causes for a debugging session, a quick sanity check, or a production incident, this tool is free to use as many times as you need. There are no watermarks, no sign-up, and no ads inside the tool itself.
Frequently asked questions
What's the difference between 401 and 403?
401 means auth is missing or invalid — try re-authenticating. 403 means the server understood who you are but you're not allowed — auth won't fix it.
When should APIs use 422 vs 400?
400 for malformed syntax (invalid JSON). 422 for well-formed but semantically invalid input (missing required field, wrong value type). Many modern JSON APIs prefer 422 for validation errors.
What does 418 I'm a teapot mean?
An April Fools' joke from RFC 2324. Some sites use it as a placeholder or easter egg — no real API should return it.
Read more
From curl to fetch, axios, and Python: the API integration workflow
Every API doc uses curl examples. Every codebase uses something else. Here's how to translate curl commands correctly — headers, auth, JSON bodies, and the flags that don't map cleanly.
HTTP status codes that actually matter for API developers in 2026
You know 200 and 500. But the difference between 401 vs 403, 400 vs 422, and 502 vs 503 decides whether your API is professional or amateur. Here's the short list that matters.
User-Agent strings in 2026: parsing, Client Hints, and privacy
The User-Agent string is a mess — Chrome pretends to be Safari, Edge pretends to be Chrome. But it's still what your analytics reads. Here's how to parse it, when to trust it, and where Client Hints are taking us.
Related tools
Lorem Ipsum
Generate placeholder text — paragraphs, sentences, or words
Cron Generator
Build and explain cron schedules visually
Password Generator
Generate strong, random passwords with a strength meter
UUID Generator
Generate one or thousands of UUIDs — v4 random or v7 time-ordered
QR Code Generator
Create custom QR codes with colors and downloadable PNG/SVG
Meta Tag Generator
Generate SEO, Open Graph, and Twitter Card meta tags with preview