Example: 200 status code
100 Continue [RFC7231, Section 6.2.1]
101 Switching Protocols [RFC7231, Section 6.2.2]
102 Processing [RFC2518]
103 Early Hints [RFC8297]
104-199 Unassigned
200 OK [RFC7231, Section 6.3.1]
201 Created [RFC7231, Section 6.3.2]
202 Accepted [RFC7231, Section 6.3.3]
203 Non-Authoritative Information [RFC7231, Section 6.3.4]
204 No Content [RFC7231, Section 6.3.5]
205 Reset Content [RFC7231, Section 6.3.6]
206 Partial Content [RFC7233, Section 4.1]
207 Multi-Status [RFC4918]
208 Already Reported [RFC5842]
209-225 Unassigned
226 IM Used [RFC3229]
227-299 Unassigned
300 Multiple Choices [RFC7231, Section 6.4.1]
301 Moved Permanently [RFC7231, Section 6.4.2]
302 Found [RFC7231, Section 6.4.3]
303 See Other [RFC7231, Section 6.4.4]
304 Not Modified [RFC7232, Section 4.1]
305 Use Proxy [RFC7231, Section 6.4.5]
306 (Unused) [RFC7231, Section 6.4.6]
307 Temporary Redirect [RFC7231, Section 6.4.7]
308 Permanent Redirect [RFC7538]
309-399 Unassigned
400 Bad Request [RFC7231, Section 6.5.1]
401 Unauthorized [RFC7235, Section 3.1]
402 Payment Required [RFC7231, Section 6.5.2]
403 Forbidden [RFC7231, Section 6.5.3]
404 Not Found [RFC7231, Section 6.5.4]
405 Method Not Allowed [RFC7231, Section 6.5.5]
406 Not Acceptable [RFC7231, Section 6.5.6]
407 Proxy Authentication Required [RFC7235, Section 3.2]
408 Request Timeout [RFC7231, Section 6.5.7]
409 Conflict [RFC7231, Section 6.5.8]
410 Gone [RFC7231, Section 6.5.9]
411 Length Required [RFC7231, Section 6.5.10]
412 Precondition Failed [RFC7232, Section 4.2][RFC8144, Section 3.2]
413 Payload Too Large [RFC7231, Section 6.5.11]
414 URI Too Long [RFC7231, Section 6.5.12]
415 Unsupported Media Type [RFC7231, Section 6.5.13][RFC7694, Section 3]
416 Range Not Satisfiable [RFC7233, Section 4.4]
417 Expectation Failed [RFC7231, Section 6.5.14]
418-420 Unassigned
421 Misdirected Request [RFC7540, Section 9.1.2]
422 Unprocessable Entity [RFC4918]
423 Locked [RFC4918]
424 Failed Dependency [RFC4918]
425 Too Early [RFC8470]
426 Upgrade Required [RFC7231, Section 6.5.15]
427 Unassigned
428 Precondition Required [RFC6585]
429 Too Many Requests [RFC6585]
430 Unassigned
431 Request Header Fields Too Large [RFC6585]
432-450 Unassigned
451 Unavailable For Legal Reasons [RFC7725]
452-499 Unassigned
500 Internal Server Error [RFC7231, Section 6.6.1]
501 Not Implemented [RFC7231, Section 6.6.2]
502 Bad Gateway [RFC7231, Section 6.6.3]
503 Service Unavailable [RFC7231, Section 6.6.4]
504 Gateway Timeout [RFC7231, Section 6.6.5]
505 HTTP Version Not Supported [RFC7231, Section 6.6.6]
506 Variant Also Negotiates [RFC2295]
507 Insufficient Storage [RFC4918]
508 Loop Detected [RFC5842]
509 Unassigned
510 Not Extended [RFC2774]
511 Network Authentication Required [RFC6585]
512-599 Unassigned
source : https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml