What are the common HTTP status codes?

HTTP Status Code Categories

HTTP status codes are three-digit numbers divided into five categories:

• 1xx: Informational
• 2xx: Success
• 3xx: Redirection
• 4xx: Client Error
• 5xx: Server Error

Common Status Codes

2xx Success

Code	Name	Description
200	OK	Request succeeded
201	Created	Resource successfully created (common with POST)
204	No Content	Success with no response body (common with DELETE)

3xx Redirection

Code	Name	Description
301	Moved Permanently	Permanent redirect, SEO passes link equity
302	Found	Temporary redirect
304	Not Modified	Resource unchanged, use cached version

4xx Client Errors

Code	Name	Description
400	Bad Request	Malformed request syntax
401	Unauthorized	Not authenticated, login required
403	Forbidden	Authenticated but no permission
404	Not Found	Resource does not exist
429	Too Many Requests	Rate limit exceeded

5xx Server Errors

Code	Name	Description
500	Internal Server Error	Server-side error
502	Bad Gateway	Invalid response from upstream server
503	Service Unavailable	Service temporarily unavailable (maintenance or overload)