HTTP Status Codes Reference
HTTP status codes are 3-digit server response identifiers, grouped into 5 categories. This table covers all common codes with descriptions.
1xx Informational2xx Success3xx Redirection4xx Client Error5xx Server Error
| Code | Name | Chinese Name | Category | Description |
|---|---|---|---|---|
| 100 | Continue | 继续 | 1xx Informational | The client should continue with the request body. |
| 101 | Switching Protocols | 切换协议 | 1xx Informational | Server agrees to switch protocols (e.g., upgrade to WebSocket). |
| 102 | Processing | 处理中 | 1xx Informational | Server received the request and is still processing it. |
| 200 | OK | 成功 | 2xx Success | The request succeeded. Most common status code. |
| 201 | Created | 已创建 | 2xx Success | Request succeeded and a new resource was created (common for POST). |
| 202 | Accepted | 已接受 | 2xx Success | Request accepted but not yet processed (async task). |
| 204 | No Content | 无内容 | 2xx Success | Request succeeded with no content returned (common for DELETE). |
| 206 | Partial Content | 部分内容 | 2xx Success | Server returns partial content (Range request). |
| 301 | Moved Permanently | 永久重定向 | 3xx Redirection | Resource permanently moved to a new URL. SEO link equity transfers. |
| 302 | Found | 临时重定向 | 3xx Redirection | Resource temporarily moved. Does not transfer SEO link equity. |
| 304 | Not Modified | 未修改 | 3xx Redirection | Resource not modified, client should use cached version. |
| 307 | Temporary Redirect | 临时重定向（保持方法） | 3xx Redirection | Temporary redirect, preserves the original request method. |
| 308 | Permanent Redirect | 永久重定向（保持方法） | 3xx Redirection | Permanent redirect, preserves the original request method. |
| 400 | Bad Request | 请求错误 | 4xx Client Error | Malformed request syntax or invalid parameters. |
| 401 | Unauthorized | 未授权 | 4xx Client Error | Authentication required. Common with missing or invalid token. |
| 403 | Forbidden | 禁止访问 | 4xx Client Error | Server refuses the request (insufficient permissions). |
| 404 | Not Found | 未找到 | 4xx Client Error | Requested resource not found. Most common client error. |
| 405 | Method Not Allowed | 方法不允许 | 4xx Client Error | HTTP method not allowed (e.g., POST to a GET-only endpoint). |
| 408 | Request Timeout | 请求超时 | 4xx Client Error | Client did not send request within server timeout. |
| 409 | Conflict | 冲突 | 4xx Client Error | Request conflicts with server state (e.g., duplicate creation). |
| 410 | Gone | 已删除 | 4xx Client Error | Resource permanently removed (more explicit than 404). |
| 413 | Payload Too Large | 请求体过大 | 4xx Client Error | Request body exceeds server limit (e.g., large file upload). |
| 415 | Unsupported Media Type | 不支持的媒体类型 | 4xx Client Error | Request Content-Type not supported by server. |
| 422 | Unprocessable Entity | 无法处理的实体 | 4xx Client Error | Well-formed but semantically erroneous request (validation failure). |
| 429 | Too Many Requests | 请求过多 | 4xx Client Error | Rate limit exceeded (throttling). |
| 500 | Internal Server Error | 服务器内部错误 | 5xx Server Error | Unexpected server error. Most common server error. |
| 501 | Not Implemented | 未实现 | 5xx Server Error | Server does not support the requested feature. |
| 502 | Bad Gateway | 网关错误 | 5xx Server Error | Gateway/proxy received invalid response from upstream. |
| 503 | Service Unavailable | 服务不可用 | 5xx Server Error | Service temporarily unavailable (overloaded or maintenance). |
| 504 | Gateway Timeout | 网关超时 | 5xx Server Error | Gateway/proxy timed out waiting for upstream. |
| 511 | Network Authentication Required | 需要网络认证 | 5xx Server Error | Network authentication required (e.g., captive portal). |
Frequently Asked Questions
What is the difference between 301 and 302?
301 is a permanent redirect that transfers SEO link equity to the new URL; 302 is temporary and usually does not transfer equity. 308 / 307 are the method-preserving (e.g. POST) counterparts.
What is the difference between 404 and 410?
404 means the resource was not found (possibly temporarily); 410 means it was permanently removed — more explicit than 404 and helps search engines clean up faster.
What is the difference between 500 and 503?
500 is an unexpected server error; 503 means the service is temporarily unavailable (overload or maintenance), usually with a Retry-After header so crawlers retry later.
What does 429 mean?
Too Many Requests — rate limiting was triggered. The client should slow down and retry according to the Retry-After header.