List of HTTP response codes.

Q. List of HTTP response codes.

Answer: 

HTTP response codes are three-digit numbers that indicate the outcome of an HTTP request made by a client to a server. Here is a list of some common HTTP response codes along with their general meanings:

1xx Informational responses:
- 100 Continue
- 101 Switching Protocols
- 102 Processing (WebDAV; RFC 2518)

2xx Success:
- 200 OK
- 201 Created
- 202 Accepted
- 203 Non-Authoritative Information
- 204 No Content
- 205 Reset Content
- 206 Partial Content
- 207 Multi-Status (WebDAV; RFC 4918)
- 208 Already Reported (WebDAV; RFC 5842)
- 226 IM Used (HTTP Delta encoding; RFC 3229)

3xx Redirection:
- 300 Multiple Choices
- 301 Moved Permanently
- 302 Found
- 303 See Other
- 304 Not Modified
- 305 Use Proxy (deprecated)
- 306 Switch Proxy
- 307 Temporary Redirect
- 308 Permanent Redirect

4xx Client Errors:
- 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 Payload Too Large
- 414 URI Too Long
- 415 Unsupported Media Type
- 416 Range Not Satisfiable
- 417 Expectation Failed
- 418 I'm a teapot (April Fools' joke; RFC 2324)
- 421 Misdirected Request
- 422 Unprocessable Entity (WebDAV; RFC 4918)
- 423 Locked (WebDAV; RFC 4918)
- 424 Failed Dependency (WebDAV; RFC 4918)
- 425 Too Early (RFC 8470)
- 426 Upgrade Required
- 428 Precondition Required
- 429 Too Many Requests
- 431 Request Header Fields Too Large
- 451 Unavailable For Legal Reasons

5xx Server Errors:
- 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; RFC 4918)
- 508 Loop Detected (WebDAV; RFC 5842)
- 510 Not Extended
- 511 Network Authentication Required

Each status code is accompanied by a default reason phrase (e.g., "OK" for 200), but custom reason phrases can also be used. These status codes and their meanings are defined in the HTTP/1.1 specification (RFC 7231) and related RFCs.