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HTTP Status Codes

Find registered HTTP response codes by number, phrase, response class, meaning, or RFC reference.

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How to use

  1. 1.Enter an exact three-digit code, a class such as 4xx, a reason phrase, a protocol term, or an RFC reference in the search box.
  2. 2.Choose Informational, Successful, Redirection, Client error, or Server error when you want to limit the matching response class.
  3. 3.Read the phrase, concise meaning, registration-state label, and RFC reference; consult the linked specification for implementation-critical details.

About HTTP Status Codes

HTTP Status Codes is a browser-based reference for the response codes registered by the Internet Assigned Numbers Authority. It contains 64 individual entries from 100 through 511 as captured from the IANA HTTP Status Code Registry on July 17, 2026. Search by an exact code, a phrase such as Not Found, a concept such as gateway, or a protocol term such as WebDAV. You can also type a class pattern such as 4xx or use the response-class selector. Filtering happens immediately in your browser, and the search text is never uploaded to Lizely or another service.

HTTP response codes are grouped into five classes according to their first digit. Informational responses occupy 100 through 199 and describe interim progress. Successful responses are in the 200 range. Redirections are in the 300 range. Codes in the 400 range describe conditions attributed to the client request, while codes in the 500 range describe server-side failures or inability to fulfill a valid request. A class is broader than one specific code: 404 Not Found and 429 Too Many Requests are both client-error responses, but they communicate different conditions and usually require different remedies.

The table is intentionally registry-based rather than a collection of every number seen in server software. It includes named individual entries in the IANA registry and excludes unassigned ranges and vendor-specific extensions. That boundary prevents a framework-specific code from being presented as an Internet standard. It also means that a three-digit value can be syntactically shaped like an HTTP status code without appearing here. For example, 105 is currently inside an unassigned range, so an exact search for 105 returns no row and the interface explains that no registered entry matched.

Registration state matters. Code 104, Upload Resumption Supported, is a temporary registration in the current IANA snapshot and is labeled Temporary rather than silently presented as permanent. IANA records 305 Use Proxy as deprecated through RFC 9110, 306 and 418 as unused, and 510 Not Extended as obsolete. The table preserves those entries because they have explicit registry rows, but their badges warn readers not to choose them as ordinary current response codes. In particular, the popular phrase associated with 418 is not the current IANA description; the registry and RFC 9110 label 418 as unused, which is what this tool displays.

The short meaning beside each code is a practical paraphrase, not a replacement for the governing specification. A response's exact semantics can depend on the request method, headers, cache state, authentication context, intermediary behavior, or an extension such as WebDAV. For example, 200 OK has method-dependent meaning, 204 No Content prohibits response content, 304 Not Modified participates in conditional caching, and 401 Unauthorized concerns missing or invalid authentication credentials despite its historical reason phrase. Follow the cited RFC when implementation details affect interoperability, security, caching, or automated retry behavior.

Exact numeric search is strict. Entering 404 returns only 404 rather than every description containing similar digits. Entering 4xx selects all individually registered entries in the client-error class; it does not fabricate rows for unassigned numbers. Text search checks the reason phrase, class, concise meaning, RFC reference, and registration state. The separate class selector combines with the text query, so searching gateway while selecting Server error returns the gateway-related server failures, while searching Not Found under Server error produces a clear empty result instead of leaving a stale table visible. No matching set is silently truncated.

Status codes communicate protocol outcomes; they do not prove the underlying cause. A 502 Bad Gateway might reflect an upstream crash, a network path problem, a proxy timeout policy, or malformed upstream output. A 429 response indicates rate limiting, but its retry behavior depends on the service and may use Retry-After. A 404 can conceal a forbidden resource, and a 500 is intentionally generic. Use server logs, request identifiers, response headers, and the relevant service documentation when diagnosing a live incident. This page does not contact a URL, inspect a server, or claim to identify an operational fault.

The data set is ordered by numeric code and tested for exactly 64 rows, unique code numbers, unique code-and-phrase pairs, ascending order, and representative values in every class. External golden cases cover boundaries, commonly used codes, sparse high values, unused entries, and the time-sensitive temporary 104 registration. The IANA registry is the source of truth for registration, RFC 9110 supplies the core HTTP semantics, and MDN provides an independent implementation-oriented cross-check. Because the registry can change, treat the snapshot date as material when evaluating a newly assigned or expired temporary code.

Methodology & sources

The embedded snapshot contains each individually named IANA registry row present on 2026-07-17, including current, temporary, deprecated, unused, and obsolete entries, while excluding unassigned ranges. Each code receives its class from the standards-defined hundred range. Exact three-digit queries match one code, an Nxx query matches a response class, and other text searches inspect the code, phrase, class, summary, reference, and state. Tests assert 64 ascending entries, unique codes, unique code-and-phrase pairs, five exact class counts, empty-result behavior, and 15 independently transcribed IANA golden cases, including every exceptional registration state. Concise meanings are standards-aligned paraphrases; the linked RFC remains authoritative for full semantics.

Frequently asked questions

Does this list include every three-digit number a server might return?
No. It includes individual entries in the IANA HTTP Status Code Registry and excludes unassigned ranges and vendor-specific extensions. A server can emit a non-standard code that is not listed here.
Why does the table show 418 as unused instead of I'm a teapot?
The current IANA registry points 418 to RFC 9110, where the code is reserved and labeled unused. The familiar teapot phrase is intentionally not presented as the current registry description.
What does the Temporary label on code 104 mean?
IANA lists Upload Resumption Supported as a temporary registration tied to an active Internet-Draft. Temporary registrations can expire or change, so the table identifies its state and snapshot date explicitly.
Can this tool diagnose why my API returned an error?
It explains registered protocol meanings but does not contact your API or inspect logs. Use the response headers, request identifier, server logs, and service documentation to determine the specific operational cause.

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