HTTP status codes
A complete HTTP status code reference from 1xx to 5xx, including non-standard codes such as 418, 429, 451, 499 and 599, with search, category filters and copy.
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Search status codes
Total 65 codes / 65
100ContinueStandardChinese meaningThe server received the request headers; the client should continue sending the body.
English meaning服务器已收到请求头，客户端应继续发送请求体。
101Switching ProtocolsStandardChinese meaningThe server is switching protocols as requested by the client.
English meaning服务器按客户端的 Upgrade 请求切换协议。
102ProcessingStandardChinese meaningWebDAV: the server has received the request and is still processing it.
English meaningWebDAV：服务器已收到请求并正在处理，暂时没有响应。
103Early HintsStandardChinese meaningReturns resource hints before the final response.
English meaning在最终响应之前先返回资源预加载提示。
200OKStandardChinese meaningThe request succeeded and the response body carries the result.
English meaning请求成功，响应内容在正文里。
201CreatedStandardChinese meaningThe request succeeded and a new resource was created; Location usually points to it.
English meaning请求成功并创建了新资源，通常配合 Location 头返回新地址。
202AcceptedStandardChinese meaningThe request was accepted but processing is not finished yet.
English meaning请求已被接受但尚未处理完成，结果稍后可用。
203Non-Authoritative InformationStandardChinese meaningThe returned metadata comes from a proxy rather than the origin server.
English meaning返回的元信息来自代理，不是源服务器的最新版本。
204No ContentStandardChinese meaningThe request succeeded but there is no body to return.
English meaning请求成功但正文为空，常用于删除或提交后的响应。
205Reset ContentStandardChinese meaningThe client should reset the document view, for example a form.
English meaning请求成功，客户端应重置当前文档的视图（如表单）。
206Partial ContentStandardChinese meaningRange request: only a part of the resource is returned.
English meaning断点续传：只返回了资源的一部分。
207Multi-StatusStandardChinese meaningWebDAV: several sub-requests each carry their own status.
English meaningWebDAV：多个子请求各有自己的状态码。
208Already ReportedStandardChinese meaningWebDAV: the members were already reported in an earlier part of the response.
English meaningWebDAV：同一集合里的成员已经在前面的响应里报告过。
226IM UsedStandardChinese meaningThe server fulfilled the request using instance manipulations.
English meaning服务器已完成实例操纵，返回增量结果。
300Multiple ChoicesStandardChinese meaningThe resource has multiple representations and the client should choose one.
English meaning请求的资源有多种表示，需要客户端选择。
301Moved PermanentlyStandardChinese meaningThe resource moved permanently; search engines update their index.
English meaning资源永久重定向到新地址，搜索引擎会更新索引。
302FoundStandardChinese meaningTemporary redirect to another address.
English meaning资源临时重定向到另一个地址。
303See OtherStandardChinese meaningRedirect to another address, which should be fetched with GET.
English meaning重定向到另一个地址，并且应该改用 GET 获取结果。
304Not ModifiedStandardChinese meaningConditional cache hit: the resource is unchanged, use the local copy.
English meaning命中协商缓存，资源没有变化，直接使用本地副本。
305Use ProxyNon-standardChinese meaningDeprecated: the resource must be accessed through a proxy.
English meaning已弃用：要求通过代理访问资源。
306UnusedNon-standardChinese meaningDeprecated: a historical code that is reserved and unused.
English meaning已废弃：历史遗留的状态码，保留未用。
307Temporary RedirectStandardChinese meaningTemporary redirect that must keep the original request method.
English meaning临时重定向，但必须保持原来的请求方法。
308Permanent RedirectStandardChinese meaningPermanent redirect that must keep the original request method.
English meaning永久重定向，同样必须保持原来的请求方法。
400Bad RequestStandardChinese meaningThe request is malformed or the parameters are invalid.
English meaning请求语法错误或参数不合法，服务器无法处理。
401UnauthorizedStandardChinese meaningNot authenticated: sign in or provide valid credentials first.
English meaning未认证：需要先登录或提供有效的凭证。
402Payment RequiredStandardChinese meaningReserved; often used for APIs that require payment.
English meaning预留状态码，常被用于需要付费才能访问的场景。
403ForbiddenStandardChinese meaningAuthenticated but not allowed to access the resource.
English meaning已认证但没有访问权限。
404Not FoundStandardChinese meaningThe requested resource does not exist.
English meaning请求的资源不存在。
405Method Not AllowedStandardChinese meaningThe resource exists but does not support this HTTP method.
English meaning资源存在，但不支持这个请求方法。
406Not AcceptableStandardChinese meaningNo representation matches the Accept header.
English meaning无法返回符合 Accept 头要求的响应。
407Proxy Authentication RequiredStandardChinese meaningThe request must authenticate with the proxy first.
English meaning需要先通过代理服务器认证。
408Request TimeoutStandardChinese meaningThe server timed out waiting for the request.
English meaning服务器等待请求超时，客户端可以重试。
409ConflictStandardChinese meaningThe request conflicts with the current state of the resource.
English meaning请求与资源当前状态冲突，例如并发写入。
410GoneStandardChinese meaningThe resource existed but has been permanently removed.
English meaning资源曾经存在但已被永久删除。
411Length RequiredStandardChinese meaningThe Content-Length header is required.
English meaning缺少 Content-Length 头。
412Precondition FailedStandardChinese meaningA precondition such as If-Match failed.
English meaning条件请求的预置条件（If-Match 等）不满足。
413Content Too LargeStandardChinese meaningThe request body exceeds the size the server accepts.
English meaning请求体超过服务器允许的大小。
414URI Too LongStandardChinese meaningThe request URL is too long.
English meaning请求的 URL 太长。
415Unsupported Media TypeStandardChinese meaningThe media type of the request body is not supported.
English meaning请求体的媒体类型不被支持。
416Range Not SatisfiableStandardChinese meaningThe requested byte range cannot be satisfied.
English meaning请求的字节范围无法满足。
417Expectation FailedStandardChinese meaningThe expectation given in the Expect header cannot be met.
English meaningExpect 头里的期望不能满足。
418I'm a teapotNon-standardChinese meaningApril Fools code: the server is a teapot and cannot brew coffee.
English meaning愚人节彩蛋状态码：服务器是一把茶壶，不能煮咖啡。
421Misdirected RequestStandardChinese meaningThe request was directed at a server that cannot serve this host.
English meaning请求被发给了无法为该域名提供服务的服务器。
422Unprocessable ContentStandardChinese meaningThe request is well-formed but semantically invalid.
English meaning请求格式正确但语义有误，无法处理。
423LockedStandardChinese meaningWebDAV: the resource is locked.
English meaningWebDAV：资源已被锁定。
424Failed DependencyStandardChinese meaningWebDAV: the request failed because a previous request failed.
English meaningWebDAV：前置请求失败，本次请求无法完成。
425Too EarlyStandardChinese meaningThe server is unwilling to process a request that might be replayed.
English meaning服务器不愿处理可能被重放的早期请求。
426Upgrade RequiredStandardChinese meaningThe client should switch to another protocol.
English meaning需要升级到其他协议才能继续。
428Precondition RequiredStandardChinese meaningThe origin server requires the request to be conditional.
English meaning要求请求带上条件头，避免并发覆盖。
429Too Many RequestsStandardChinese meaningToo many requests in a short time: rate limited.
English meaning短时间内请求过多，已被限流，请稍后重试。
431Request Header Fields Too LargeStandardChinese meaningThe request header fields are too large.
English meaning请求头总大小超出限制。
451Unavailable For Legal ReasonsStandardChinese meaningThe resource cannot be provided for legal reasons.
English meaning因法律原因无法提供该资源。
499Client Closed RequestNon-standardChinese meaningNon-standard (nginx): the client closed the connection before the response.
English meaning非标准（nginx）：客户端在服务器响应前断开了连接。
500Internal Server ErrorStandardChinese meaningAn unexpected error occurred on the server.
English meaning服务器内部错误，通常是代码异常。
501Not ImplementedStandardChinese meaningThe server does not support the functionality required.
English meaning服务器不支持该请求需要的功能。
502Bad GatewayStandardChinese meaningThe gateway received an invalid response from the upstream server.
English meaning网关或代理从上游收到了无效响应。
503Service UnavailableStandardChinese meaningThe server is temporarily unavailable, for example overloaded or in maintenance.
English meaning服务暂时不可用，通常是过载或维护中。
504Gateway TimeoutStandardChinese meaningThe gateway timed out waiting for the upstream server.
English meaning网关等待上游响应超时。
505HTTP Version Not SupportedStandardChinese meaningThe HTTP protocol version used in the request is not supported.
English meaning服务器不支持请求使用的 HTTP 版本。
506Variant Also NegotiatesStandardChinese meaningTransparent content negotiation results in a circular reference.
English meaning内容协商配置错误，导致循环引用。
507Insufficient StorageStandardChinese meaningWebDAV: the server cannot store the representation needed.
English meaningWebDAV：服务器存储空间不足。
508Loop DetectedStandardChinese meaningWebDAV: an infinite loop was detected while processing the request.
English meaningWebDAV：处理请求时检测到死循环。
510Not ExtendedStandardChinese meaningFurther extensions to the request are required.
English meaning需要对请求做进一步扩展才能满足策略。
511Network Authentication RequiredStandardChinese meaningThe client needs to authenticate, for example on a captive portal.
English meaning需要先通过网络的认证（例如公共 Wi-Fi 登录）。
599Network Connect Timeout ErrorNon-standardChinese meaningNon-standard: the proxy timed out connecting upstream.
English meaning非标准：代理连接上游超时（常见于 nginx 日志）。
What this tool does
- Look up an unfamiliar status code from an API response or a log full of 4xx/5xx errors and see the standard reason phrase plus what it means for the client and server.
- Write API docs or an error-code table and copy the canonical reason phrases (404 Not Found, 429 Too Many Requests) instead of inventing your own.
- Check where non-standard codes come from when reading an nginx access log — 499 and 599 are nginx conventions, not RFC definitions.
- Teach or learn HTTP by browsing the 1xx–5xx categories, including the difference between 401 (not authenticated) and 403 (authenticated but not allowed).
Example
Input
404
Output
404 Not Found The requested resource does not exist. Category: 4xx client error · standard code
Digits match exactly first and fall back to a prefix match: 404 returns this single entry, while 4 lists all 30 codes in the 4xx range. For keyword lookups type a word — "timeout" hits 408, 504 and 599.
Frequently asked questions
What is the real difference between 401 and 403?
401 Unauthorized means "not authenticated yet": the server sends a WWW-Authenticate header telling you how to authenticate. 403 Forbidden means you are authenticated but not allowed, so logging in again will not help. The accurate name for 401 would be Unauthenticated — the misleading one is a spec legacy.
How do I decide whether a 4xx or a 5xx is at fault?
A 4xx says the request itself is wrong, and repeating it unchanged will usually fail again — fix the request first. A 5xx says the server broke, so the client may retry with backoff. 502 and 504 usually come from the gateway-to-upstream hop, and both 429 and 503 carry a Retry-After telling you how long to wait.
Why are 418, 499 and 599 marked non-standard?
Because they are not in the IETF registry. 418 I'm a teapot is an April Fools joke from RFC 2324 in 1998, while 499 and 599 are defined by nginx (client closed the request early, proxy timed out connecting upstream). They belong in logs, not in a public API contract.
Why does 304 have no response body?
304 Not Modified is the outcome of conditional caching: the browser asks with If-None-Match or If-Modified-Since, the server sees the resource is unchanged and replies with 304 so the local copy is reused, saving the transfer. That is why it has no payload and usually no Content-Type either.
Can I search with a phrase instead of a number?
Yes. Non-numeric input is matched case-insensitively against the reason phrase, the Chinese meaning and the English description, so words like "redirect", "timeout" or "rate" all work. Numeric input uses exact then prefix matching, so a mixed string such as 4xx will not match.
Keywords：httpstatus code状态码http 状态码404500http status响应码rest