HTTP Status Code Lookup

What Is the HTTP Status Code Lookup?

HTTP status codes communicate the outcome of a web request in a standardized 3-digit number. This tool looks up any code's meaning instantly, with a full reference table of the most common codes for quick browsing.

How to Use This Tool

Enter a status code (like 404 or 500). Its meaning appears instantly, alongside a reference table of other common codes.

Understanding Status Code Ranges

Practical Uses

• Quickly understanding what a status code means while debugging an API response
• Choosing the correct status code to return from your own API endpoint
• Learning the standard HTTP status code categories and their meanings

For a related but distinct reference on redirect status codes specifically, see the .htaccess & Nginx Redirect Generator, which writes 301, 302, 307, 308 and 410 rules for Apache and Nginx.

Which Codes This Tool Covers

The lookup contains a curated set of the most common codes: 200, 201, 204, 301, 302, 304, 400, 401, 403, 404, 405, 409, 422, 429, 500, 502, 503, and 504. If you enter anything else, such as 418 or 307, the result reads "Unknown or non-standard status code". That message means the code is not in this table, not that it is invalid in HTTP. For anything outside the list, consult the official HTTP specifications or your framework documentation.

Choosing the Right Code for Your Own API

• Use 200 for a successful read or update that returns data, 201 when a POST created something new, and 204 when the action succeeded and there is nothing to send back.
• Use 400 when the request is malformed, and 422 when the request is well-formed but its values fail validation, such as an email field with an invalid address.
• Use 401 when credentials are missing or invalid, and 403 when the caller is known but not allowed.
• Use 404 when the resource does not exist, and 409 when the request clashes with the current state, for example creating a record whose unique value is already taken.
• Use 429 to tell a client it has hit a rate limit.

Debugging With the Codes

When a request fails, start with the first digit. A 4xx means the fault is in what was sent, so look at the URL, method, headers, authentication, and body. A 5xx means the server or something behind it failed, so look at server logs, upstream services, and timeouts. Within 5xx, 502 and 504 point at a gateway or proxy that could not get a good, timely answer from a service behind it, whereas a plain 500 suggests an unhandled error inside the application. A 503 usually indicates temporary overload or maintenance, and the client can often retry after a delay.

Redirect Behavior Worth Knowing

A 301 tells browsers and search engines to treat the new URL as the permanent location, while a 302 says the move is temporary. Using a temporary code for a permanent move can slow down how quickly search engines transfer ranking signals, so pick deliberately. A 304 is not an error: it tells the client its cached copy is still current.

Common Mistakes

• Returning 200 with an error message in the body. Clients and monitoring tools rely on the status code, so use the appropriate 4xx or 5xx.
• Confusing 401 and 403, which changes what the client should do next.
• Assuming the number field accepts text. It takes a numeric code only, so enter 404 rather than "Not Found".

Limits

The descriptions are short summaries. They do not replace the full definitions, and some codes have nuances, such as which methods they apply to, that are not captured here.

Frequently Asked Questions