Most common HTTP error codes (status codes), which indicate issues during communication between the client and the server. These codes are grouped based on the type of issue they represent:
1xx: Informational Responses
These codes indicate that the server has received the request and is continuing the process.
- 100 Continue: The server has received the request headers, and the client should proceed to send the request body.
- 101 Switching Protocols: The server is switching protocols as requested by the client.
2xx: Success
These codes indicate that the request was successfully received, understood, and processed.
- 200 OK: The request was successful, and the server responded with the requested data.
- 201 Created: The request was successful, and a new resource was created.
- 204 No Content: The request was successful, but there is no content to return.
3xx: Redirection
These codes indicate that further action is needed to complete the request, typically a redirection to another URL.
- 301 Moved Permanently: The resource has been permanently moved to a new location (use the new URL).
- 302 Found: The resource has been temporarily moved (the client should use the original URL in the future).
- 304 Not Modified: The resource has not been modified since the last request, so the client can use the cached version.
4xx: Client Errors
These codes indicate that the client has made an error in the request.
- 400 Bad Request: The request was malformed or missing required parameters.
- 401 Unauthorized: The client must authenticate to access the resource (e.g., login).
- 403 Forbidden: The client is authenticated but does not have permission to access the resource.
- 404 Not Found: The requested resource could not be found on the server.
- 405 Method Not Allowed: The HTTP method used is not supported by the resource.
- 408 Request Timeout: The server timed out waiting for the client’s request.
- 409 Conflict: The request could not be processed due to a conflict with the current state of the resource.
- 413 Payload Too Large: The request is too large for the server to process.
- 414 URI Too Long: The request URI is too long for the server to process.
- 415 Unsupported Media Type: The server does not support the media type of the request.
- 429 Too Many Requests: The client has sent too many requests in a given period.
5xx: Server Errors
These codes indicate that the server has encountered an error or is unable to perform the request.
- 500 Internal Server Error: A generic error indicating a problem with the server.
- 501 Not Implemented: The server does not support the functionality required to fulfill the request.
- 502 Bad Gateway: The server received an invalid response from the upstream server.
- 503 Service Unavailable: The server is temporarily unavailable, often due to maintenance or overload.
- 504 Gateway Timeout: The server did not receive a timely response from an upstream server.
- 505 HTTP Version Not Supported: The server does not support the HTTP protocol version used in the request.
