Question 1

What are HTTP status codes?

Accepted Answer

HTTP status codes are 3-digit numbers returned by a web server in response to a client request. They indicate whether the request was successful, whether a redirect is needed, or whether an error occurred on the client or server side.

Question 2

What is the difference between 401 and 403?

Accepted Answer

401 Unauthorized means the client is not authenticated — it needs to provide credentials. 403 Forbidden means the server understands the request and knows who the client is, but refuses to allow access. Authentication won't help with a 403.

Question 3

What is the difference between 301 and 302?

Accepted Answer

301 Moved Permanently tells clients and search engines that a URL has permanently moved to a new location. 302 Found is a temporary redirect. For SEO purposes, 301 passes link equity to the new URL, while 302 does not.

Question 4

What does 418 I'm a Teapot mean?

Accepted Answer

418 is an April Fools' joke from RFC 2324 (Hyper Text Coffee Pot Control Protocol). It means the server refuses to brew coffee because it is a teapot. It is not a real HTTP error — but many servers implement it humorously.

Question 5

What is the difference between 500, 502, 503, and 504?

Accepted Answer

500 Internal Server Error is a generic server-side failure. 502 Bad Gateway means a proxy received an invalid response from an upstream server. 503 Service Unavailable means the server is temporarily unavailable (overloaded or in maintenance). 504 Gateway Timeout means a proxy did not get a response in time from the upstream server.

HTTP Status Codes

HTTP Status Codes