HTTP Status Code Lookup

A quick reference for common response codes

This HTTP status code lookup presents a fixed table of selected response codes with a category, code number, name, description, and additional note. Use the table search to find a displayed number or term, sort a column to scan the entries, or move through the pages. It is a reference list rather than a live website checker: entering a domain or URL will not send an HTTP request or report whether a site is online.

HTTP response status codes are three-digit values from 100 through 599. Their first digit identifies the response class: 1xx informational, 2xx successful, 3xx redirection, 4xx client error, and 5xx server error. The class is useful context, but the code alone does not explain every server’s behavior or the cause of a particular response.

Use the table without assuming it is exhaustive

The built-in list contains selected common and historical entries; it does not mirror every value in the IANA registry. HTTP status codes are extensible, and additional codes can be registered or defined by other specifications. When a code is missing, consult the current IANA registry and its cited specification rather than inferring that the value is invalid.

Some wording in a static reference may reflect older terminology or an older description. The current HTTP semantics specification and registry are the authority for protocol meaning and current registration status. In particular, a table entry is a concise explanation, not a substitute for the full rule text.

How to interpret a result

Read the category first, then compare the code’s name and note. A 200 response is in the successful class, a 404 is in the client-error class, and a 500 is in the server-error class. These broad labels help orient troubleshooting, but a 404 does not by itself tell you whether a missing resource is temporary, and a 500 does not identify the underlying server fault.

When diagnosing an actual request, inspect the response headers, body, request method, and relevant application logs as well as the status code. A response can be generated by an origin server, proxy, gateway, or application layer, and the same code can appear in different situations.

Find a code or phrase

1. Search the visible table

   Enter a number such as 404 or a word from a displayed name or description. The search filters the current reference rows.

2. Sort to scan

   Select a column heading to sort the table, then use the page controls to browse the displayed records.

3. Check an authoritative definition

   For implementation or incident work, match the code to the current RFC or registry entry and read the specification section it cites.

When an external source is needed

Use the RFC for normative semantics and IANA for registration and references. A quick table is useful for orientation, but the response from your own request and the server’s logs provide the evidence needed to explain a live failure. This lookup does not test URLs, inspect response headers, or diagnose a server.

Look up a response code

1. Search by number or phrase

   Use a known code or a term from the table. Search is limited to the records shown in this reference.

2. Read the category and note

   Use the class to orient the result, then read the description for the specific code. Do not treat a class label as a diagnosis of a live request.

3. Verify protocol details

   Follow the RFC reference or current IANA registry entry when exact behavior, registration, or updated wording matters.

Questions about the lookup

Reference scope

This page is a selected static reference, not a live HTTP test, exhaustive registry, or incident diagnosis.

• A status code alone may not reveal the cause or permanence of a response. Check the response details and server context.
• Codes outside the table may still be valid or registered. Confirm them through IANA and the cited standard.
• For protocol implementation, security review, or production troubleshooting, rely on the applicable current specification and your own request evidence.