HTTP Status Code Lookup

Look up any HTTP status code — 200, 404, 500, and everything in between — with a plain-English explanation of what it means and when servers return it.

What is HTTP Status Code Lookup?

HTTP status codes are the three-digit numbers a web server sends back with every response, telling the client (browser, app, or API consumer) whether the request succeeded, needs a redirect, or failed — and why. They're standardized by the IETF and used identically across every web server, browser, and programming language, which makes them one of the most universal debugging references in software development.

This lookup tool covers the most commonly encountered codes across all five categories — informational (1xx), success (2xx), redirection (3xx), client error (4xx), and server error (5xx) — with plain-English explanations of what each one actually means in practice, not just the formal RFC definition.

Formula

1xx: Informational — request received, continuing process

2xx: Success — request was successfully received and accepted

3xx: Redirection — further action needed to complete the request

4xx: Client Error — request contains bad syntax or cannot be fulfilled

5xx: Server Error — server failed to fulfill a valid request

How to Calculate

Type a status code (like 404) or a keyword (like "forbidden") into the search box.
Filter by category using the 1xx-5xx buttons if you want to browse a specific range.
Read the plain-English description of what the code means and when it's typically returned.
Use this as a quick reference while debugging API responses or building error handling.

Example

Searching "429" returns "Too Many Requests" — the code APIs return when you've exceeded a rate limit, telling you to slow down and retry after a delay.

Key Benefits

Every commonly used status code in one searchable reference
Plain-English explanations, not just formal RFC wording
Filter instantly by category (1xx through 5xx)
Free, fast, no sign-up required

Common Mistakes to Avoid

Returning 200 OK for a request that actually failed, hiding errors from monitoring tools
Confusing 401 (not authenticated) with 403 (authenticated but not authorized)
Using 302 for a redirect that should be permanent (301), hurting SEO
Treating all 4xx and 5xx errors the same in client-side error handling instead of branching on the specific code

Pro Tips

Reserve 5xx codes strictly for server-side failures — never use them to signal client input errors
Use 429 with a Retry-After header when rate-limiting, so well-behaved clients know when to retry
Prefer 404 over a generic error page whenever a resource genuinely doesn't exist — it's better for both users and search engines
When designing an API, pick specific 4xx codes (422, 409, 400) rather than defaulting everything to a generic 400

Key Terms Explained

Status line: The first line of an HTTP response, containing the status code and a short reason phrase
Idempotent: A property of certain HTTP methods where repeating the same request has the same effect as doing it once
Redirect chain: A sequence of multiple redirects a browser follows before reaching the final resource
Rate limiting: Restricting how many requests a client can make in a given time window, often signaled with 429

Common Use Cases

Quickly understanding an unfamiliar status code returned by an API you're integrating with
Deciding which status code to return from your own API for a given error condition
Debugging why a request is failing by checking what a specific code actually implies
Teaching or learning HTTP fundamentals in a web development course
Writing accurate error-handling logic that distinguishes between different 4xx and 5xx cases

Frequently Asked Questions

What do the different HTTP status code ranges mean?

1xx codes are informational, 2xx mean success, 3xx indicate redirection, 4xx mean the client made an error (like requesting a missing page), and 5xx mean the server itself failed to fulfill a valid request.

What's the difference between 401 and 403?

401 Unauthorized means you haven't authenticated (or your credentials are invalid) — the server doesn't know who you are. 403 Forbidden means the server knows who you are but you don't have permission to access the resource.

Why do I sometimes see 200 for a page that clearly failed to load?

This usually means the server returned a valid HTTP response (hence 200 OK) but the application-level content of that response describes an error — a common pattern in APIs that put error details in the response body instead of the status code.

What's the difference between 301 and 302 redirects?

301 Moved Permanently tells browsers and search engines to update their records and use the new URL going forward. 302 Found signals a temporary redirect — the original URL should still be used for future requests.