HTTP status codes are a series of numerical codes used by servers to inform clients about the result of request processing. These status codes are divided into five main categories: informational status codes, success status codes, redirection status codes, client error status codes, and server error status codes. Each category has specific meanings that help clients understand the status of their requests.

1. Informational responses (100 – 199)
100 Continue
101 Switching Protocols
102 Processing
103 Early Hints
2. Successful responses (200 – 299)
200 OK
201 Created
202 Accepted
203 Non-Authoritative Information
204 No Content
205 Reset Content
206 Partial Content
207 Multi-Status (WebDAV)
208 Already Reported (WebDAV)
226 IM Used (HTTP Delta encoding)
3. Redirection messages (300 – 399)
300 Multiple Choices
301 Moved Permanently
302 Found
303 See Other
304 Not Modified
305 Use Proxy
306 Unused
307 Temporary Redirect
308 Permanent Redirect
4. Client error responses (400 – 499)
400 Bad Request
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 Not Acceptable
407 Proxy Authentication Required
408 Request Timeout
409 Conflict
410 Gone
411 Length Required
412 Precondition Failed
413 Content Too Large
414 URI Too Long
415 Unsupported Media Type
416 Range Not Satisfiable
417 Expectation Failed
418 I'm a teapot
421 Misdirected Request
422 Unprocessable Content (WebDAV)
423 Locked (WebDAV)
424 Failed Dependency (WebDAV)
425 Too Early
426 Upgrade Required
428 Precondition Required
429 Too Many Requests
431 Request Header Fields Too Large
451 Unavailable For Legal Reasons
5. Server error responses (500 – 599)
500 Internal Server Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Timeout
505 HTTP Version Not Supported
506 Variant Also Negotiates
507 Insufficient Storage (WebDAV)
508 Loop Detected (WebDAV)
510 Not Extended
511 Network Authentication Required