100Information
Continue
The request headers arrived; the client may continue sending the request body.
Use when: Useful for streaming or large uploads.
HTTP REFERENCE
Find the right HTTP status code
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23 codes
101Information
Switching Protocols
The server agrees to change protocols requested by the client.
Use when: Commonly used to establish a WebSocket connection.
200Success
OK
The request succeeded.
Use when: Use for a successful read or an action with a response body.
201Success
Created
The request succeeded and created a new resource.
Use when: Return after a successful POST, usually with a Location header.
202Success
Accepted
The request was accepted for processing, but processing is not complete.
Use when: Use for queued or asynchronous work.
204Success
No Content
The request succeeded and there is no response body to return.
Use when: Useful after DELETE or an update that needs no representation.
301Redirection
Moved Permanently
The resource has a new permanent URL.
Use when: Use when a URL should be replaced and search engines should update their links.
302Redirection
Found
The resource is temporarily available at another URL.
Use when: Use for a temporary redirect; preserve the original URL for future requests.
304Redirection
Not Modified
The cached representation is still fresh.
Use when: Return for a conditional request when the resource has not changed.
307Redirection
Temporary Redirect
The resource is temporarily available at another URL and the method must remain unchanged.
Use when: Use when a POST or other method must not be changed to GET.
308Redirection
Permanent Redirect
The resource has a new permanent URL and the method must remain unchanged.
Use when: Use for a permanent method-preserving redirect.
400Client error
Bad Request
The server cannot process the request because it is malformed or invalid.
Use when: Check syntax, required fields, and request parsing.
401Client error
Unauthorized
The request lacks valid authentication credentials.
Use when: The client should authenticate or refresh its credentials.
403Client error
Forbidden
The server understood the request but refuses to fulfill it.
Use when: Authentication may be present, but permission is missing.
404Client error
Not Found
The server cannot find the requested resource.
Use when: Check the URL, route, identifier, or whether the resource was removed.
405Client error
Method Not Allowed
The resource exists but does not support this request method.
Use when: Check the Allow header and the endpoint contract.
409Client error
Conflict
The request conflicts with the current state of the resource.
Use when: Resolve a version, uniqueness, or state conflict before retrying.
422Client error
Unprocessable Content
The request syntax is valid, but its instructions cannot be processed.
Use when: Return field or business-rule validation errors.
429Client error
Too Many Requests
The client sent too many requests in a given period.
Use when: Back off, respect Retry-After, and apply client-side rate limits.
500Server error
Internal Server Error
The server encountered an unexpected condition.
Use when: Inspect server logs and return a safe error body.
502Server error
Bad Gateway
A gateway received an invalid response from an upstream server.
Use when: Check the proxy, upstream health, and timeout behavior.
503Server error
Service Unavailable
The server is not ready to handle the request.
Use when: Use during overload or maintenance and include Retry-After when useful.
504Server error
Gateway Timeout
A gateway did not receive a timely response from an upstream server.
Use when: Check upstream latency, connection limits, and timeout settings.
QUICK GUIDE
Choose a response that tells the truth
Use 2xx when the server completed the request.
Use 3xx when the client should look elsewhere or use its cache.
Use 4xx when the request cannot be accepted as sent.
Use 5xx when the server or an upstream dependency failed.
FAQ
HTTP status code questions
What is the difference between 401 and 403?
401 means valid authentication is missing. 403 means the server knows who the client is but will not allow the action.
When should I use 422 instead of 400?
Use 400 for a malformed request. Use 422 when the request is well-formed but fails validation or a business rule.
Why use 307 or 308?
They preserve the original request method during a redirect, which matters for POST, PUT, and other non-GET requests.