Abstract
2XX
201
- Created
- Requested resource is created successfully
204
- No Content
- Server successfully processed the HTTP Request, but isn’t returning any content
218
- This is Fine
- Specifically for Apache servers that serve as a Reverse Proxy (反向代理) with
ProxyErrorOverride on
- For example, The Server behind Apache can send the 218 status code, so the Client will receive 218 even when there is an error code like 404
3XX
301
- Permanent Redirect
- Telling the Client (usually a web browser or a web crawler) that the requested resource has moved permanently to a new location
- One use case is when clients accessing via HTTP, but server only wants to serve via HTTPS
302
- Temporary Redirect
- The redirected page isn’t going to be indexed by search engine. The page that performs the redirects is
- If you need to permanently move a page to a new location, we should use 301
- Use cases are Temporary Maintenance and A/B Testing
4XX
- Indicates the Client-side has some issues
400
- Bad Request
- The HTTP Request cannot be fulfilled due to bad syntax.
401
- Unauthorised
- You need to provide valid credentials (e.g., login information) to access this resource, and the ones you provided are not accepted
403
- Forbidden
- Happens when the provided Authentication information is rejected
404
- Unfound
- Resources can’t be found on Server
409
- Conflict
- Returned when the same resource is being processed
- Same user is created
- Concurrency Conflicts
418
- I’m a teapot
- Indicates that the Server refuses to brew coffee because it is, permanently, a teapot
420
- Enhance Your Calm
- Can be used to tell Client it is being rated limited for making too many requests
- Replaced by 429
429
- Too Many Requests
- Returned when a request can’t be served due to rate limiting
451
- Unavailable for legal reasons
- Reference to Fahrenheit 451
- The user agent requested a resource that cannot legally be provided, such as a web page censored by a government. Or like Netflix geo-lock
- Usually can be solved with a VPN
5XX
- Indicates the Server-side has some issues
500
- Internal Server Error
- Some errors on the Server
502
504
- Gateway Timeout
- Indicates that a Proxy, didn’t receive a timely response from an upstream server it needed to access in order to complete the request
530
- Site Fronzen
- Can be used when the site owner’s free trial ends, the platform freezes the public access
References
- HTTP Status Codes that should never have been created
