Question 1

What is the difference between GET and POST?

Accepted Answer

GET retrieves data without modifying server state — it is safe and idempotent. POST submits data that creates or changes server state and is neither safe nor idempotent. GET parameters go in the URL; POST data goes in the request body.

Question 2

What does idempotent mean for HTTP methods?

Accepted Answer

An idempotent method produces the same result whether it is called once or many times. GET, PUT, DELETE, HEAD, OPTIONS, and TRACE are idempotent. POST and PATCH are not — calling POST twice may create two resources.

Question 3

When should I use PUT vs PATCH?

Accepted Answer

Use PUT when you want to replace an entire resource with the new representation. Use PATCH when you want to apply a partial update — only the fields provided in the request body are changed.

Question 4

What is the purpose of the OPTIONS method?

Accepted Answer

OPTIONS asks the server which HTTP methods are allowed for a given URL. Browsers use it automatically in CORS preflight requests to check whether a cross-origin request is permitted before sending the actual request.

Question 5

Is DELETE safe to call multiple times?

Accepted Answer

DELETE is idempotent: deleting a resource that no longer exists returns 404 but has no further side effects. However it is not safe — the first successful call does modify server state by removing the resource.

HTTP Methods Reference

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