HTTP Status Codes & Headers
Search and inspect HTTP response status codes and security headers with developer explanations.
Continue
Initial part of request received, client can continue.
Sent to indicate that the initial part of a request has been received and has not yet been rejected by the server.
Switching Protocols
Server is switching protocols (e.g. WebSocket upgrade).
Sent in response to an Upgrade request header from the client to indicate the protocol the server is switching to.
Early Hints
Preloading critical page resources before final headers.
Used to return some response headers before final HTTP message, allowing browser to preload resources.
OK
The request has succeeded.
Standard response for successful HTTP requests. The payload depends on the method (GET, POST, etc.).
Created
Resource successfully created (POST/PUT).
The request has succeeded and has led to the creation of a new resource, typically referenced in the Location header.
Accepted
Request accepted for asynchronous background processing.
The request has been accepted for processing, but the processing has not been completed.
No Content
Action succeeded, no response body returned.
The server has successfully fulfilled the request and there is no additional content to send in the response payload body.
Partial Content
Range header partial byte request fulfilled.
Sent in response to a Range header from the client when downloading large media or resuming downloads.
Moved Permanently
Resource permanently moved to a new URI.
The target resource has been assigned a new permanent URI and any future references to this resource should use one of the returned URIs.
Found
Temporary redirect to a different URI.
Tells the client to look at (browse to) another URL temporarily.
Not Modified
Cached version is still fresh and valid (ETag/If-Modified-Since).
Indicates that the resource has not been modified since the version specified by the request headers If-Modified-Since or If-None-Match.
Temporary Redirect
Temporary redirect preserving original HTTP method (e.g. POST).
Directs client to request URI with same method as used in the original request.
Permanent Redirect
Permanent redirect preserving original HTTP method.
The request and all future requests should be repeated using another URI, retaining original HTTP verb.
Bad Request
Malformed syntax, invalid JSON, or invalid parameters.
The server cannot or will not process the request due to something that is perceived to be a client error (e.g., malformed request syntax, invalid request message framing).
Unauthorized
Authentication credentials required or invalid.
Similar to 403 Forbidden, but specifically for use when authentication is required and has failed or has not yet been provided.
Forbidden
Authenticated client lacks permission for the resource.
The client does not have access rights to the content; that is, it is unauthorized, so the server is refusing to give the requested resource.
Not Found
Requested resource could not be found.
The server has not found anything matching the Request-URI. In APIs, this means the endpoint or identifier doesn't exist.
Method Not Allowed
HTTP verb (GET/POST/DELETE) not supported by endpoint.
The request method is known by the server but is not supported by the target resource.
Request Timeout
Server timed out waiting for the client request.
The server did not receive a complete request message within the time that it was prepared to wait.
Conflict
Request conflicts with current state of resource (e.g. duplicate key).
Indicates that the request could not be processed because of conflict in the current state of the resource.
Unprocessable Entity
Semantic validation errors in request body.
The server understands the content type of the request entity, and the syntax is correct, but was unable to process the contained instructions.
Too Many Requests
Rate limit exceeded.
The user has sent too many requests in a given amount of time (rate limiting). Usually paired with Retry-After header.
Internal Server Error
Generic server-side unexpected condition or crash.
A generic error message, given when an unexpected condition was encountered and no more specific message is suitable.
Bad Gateway
Upstream server returned an invalid response.
The server, while acting as a gateway or proxy, received an invalid response from the inbound server it accessed while attempting to fulfill the request.
Service Unavailable
Server overloaded or down for maintenance.
The server is currently unable to handle the request due to a temporary overloading or maintenance of the server.
Gateway Timeout
Upstream server did not reply in time.
The server, while acting as a gateway or proxy, did not receive a timely response from an upstream server.