What is the difference between 401 and 403?

401 Unauthorized means the client has not provided valid authentication credentials. 403 Forbidden means the client IS authenticated but does not have permission to access the resource. Use 401 for "who are you?" and 403 for "you cannot do that."

When should I use 404 vs 410?

404 means the resource was not found (may exist in the future). 410 Gone means the resource existed before but has been permanently deleted. Use 410 to tell search engines to remove the page from their index.

What is the difference between 301 and 308?

301 allows the method to change (POST may become GET). 308 guarantees the method is preserved. Use 308 when redirecting API endpoints to ensure POST requests remain POST. Use 301 for general page redirects.

Last updated: April 12, 2026

HTTP Status Codes Cheatsheet

Quick Answer

HTTP status codes are 3-digit numbers returned by servers. 1xx = informational, 2xx = success, 3xx = redirection, 4xx = client error, 5xx = server error. This cheatsheet covers the 30 most important codes.

1xx Informational

Command	Description
100 Continue	Server received request headers; client should send body
101 Switching Protocols	Server is switching protocols (e.g., to WebSocket)

2xx Success

Command	Description
200 OK	Request succeeded — standard success response
201 Created	Request succeeded and a new resource was created
202 Accepted	Request accepted for processing but not yet completed
204 No Content	Request succeeded but no content to return
206 Partial Content	Returning partial resource (range request)

3xx Redirection

Command	Description
301 Moved Permanently	Resource permanently moved to a new URL (cached by browsers)
302 Found	Resource temporarily at a different URL
303 See Other	Redirect to another resource using GET (after POST)
304 Not Modified	Resource has not changed — use cached version
307 Temporary Redirect	Temporary redirect preserving the HTTP method
308 Permanent Redirect	Permanent redirect preserving the HTTP method

4xx Client Error

Command	Description
400 Bad Request	Server cannot process the request due to client error (malformed syntax)
401 Unauthorized	Authentication required — no valid credentials provided
403 Forbidden	Server refuses to authorize the request (authenticated but not allowed)
404 Not Found	Requested resource does not exist
405 Method Not Allowed	HTTP method not supported for this endpoint
408 Request Timeout	Server timed out waiting for the request
409 Conflict	Request conflicts with the current state of the resource
413 Payload Too Large	Request body exceeds server limits
415 Unsupported Media Type	Content-Type not supported by the endpoint
422 Unprocessable Entity	Request is well-formed but semantically invalid (validation error)
429 Too Many Requests	Rate limit exceeded — slow down

5xx Server Error

Command	Description
500 Internal Server Error	Generic server error — something went wrong
501 Not Implemented	Server does not support the requested functionality
502 Bad Gateway	Server got an invalid response from an upstream server
503 Service Unavailable	Server is temporarily unavailable (maintenance or overload)
504 Gateway Timeout	Upstream server did not respond in time
511 Network Authentication Required	Client needs to authenticate to access the network (captive portal)

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