List of All Known HTTP Status Codes (HTTP/1.1, HTTP/2 and HTTP/3) as of 20.12.2020, includes non-standard ones too.
1xx: Informational, 2xx: Success, 3xx: Redirection, 4xx: Client Error, 5xx: Server Error
TL;DR: Most common codes are 200 for OK, 307 for Temporary Redirect, 308 for Permanent Redirect, 403 for Forbidden, 404 for Not Found, 405 for Method Not Allowed, 429 for Rate-Limit thingies, and 500 for generic server errors.
| Code | Name | Comment |
|---|---|---|
| 100 | Continue | - |
| 101 | Switching Protocols | - |
| 102 | Processing | - |
| 103 | Early Hints | - |
| 200 | OK | - |
| 201 | Created | - |
| 202 | Accepted | - |
| 203 | Non-Authoritative Information | - |
| 204 | No Content | - |
| 205 | Reset Content | - |
| 206 | Partial Content | - |
| 207 | Multi-Status | - |
| 208 | Already Reported | - |
| 218 | This is fine | Apache |
| 226 | IM Used | - |
| 300 | Multiple Choices | - |
| 301 | Moved Permanently | - |
| 302 | Found | HTTP/1.1+ |
| 303 | See Other | - |
| 304 | Not Modified | - |
| 305 | Use Proxy | - |
| 306 | Switch Proxy | Deprecated, Reserved |
| 307 | Temporary Redirect | - |
| 308 | Permanent Redirect | Preserves POST data too, unlike 301 |
| 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 | Had a different name in HTTP/1.0 |
| 414 | URI Too Long | Had a different name in HTTP/1.0 |
| 415 | Unsupported Media Type | - |
| 416 | Range Not Satisfiable | Had a different name in HTTP/1.0 |
| 417 | Expectation Failed | - |
| 418 | I'm a teapot | - |
| 419 | Page Expired | - |
| 420 | Method Failure | - |
| 421 | Misdirected Request | - |
| 422 | Unprocessable Entity | - |
| 423 | Locked | - |
| 424 | Failed Dependency | - |
| 425 | Too Early | - |
| 426 | Upgrade Required | - |
| 428 | Precondition Required | - |
| 429 | Too Many Requests | - |
| 430 | Request Header Fields Too Large | Non-Standard |
| 431 | Request Header Fields Too Large | - |
| 440 | Login Time-out | - |
| 444 | No Response | - |
| 449 | Retry With | - |
| 450 | Blocked by Windows Parental Controls | - |
| 451 | Unavailable For Legal Reasons | - |
| 494 | Request Header Too Large | - |
| 495 | SSL Certificate Error | - |
| 496 | SSL Certificate Required | - |
| 497 | HTTP Request Sent to HTTPS Port | - |
| 498 | Invalid Token | - |
| 499 | Token Required | - |
| 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 | - |
| 508 | Loop Detected | - |
| 509 | Bandwidth Limit Exceeded | - |
| 510 | Not Extended | - |
| 511 | Network Authentication Required | - |
| 520 | Web Server Returned an Unknown Error | - |
| 521 | Web Server Is Down | - |
| 522 | Connection Timed Out | - |
| 523 | Origin Is Unreachable | - |
| 524 | A Timeout Occurred | - |
| 525 | SSL Handshake Failed | - |
| 526 | Invalid SSL Certificate | - |
| 527 | Railgun Error | - |
| 528 | Unknown Error | Unknown |
| 529 | Site is overloaded | - |
| 530 | Site is frozen | - |
| 598 | Network read timeout error | - |