Question: Which HTTP Methods Are Idempotent?

What is the difference between safe and idempotent HTTP methods?

2 Answers.

Safe methods are methods that can be cached, prefetched without any repercussions to the resource.

idempotent HTTP method is a HTTP method that can be called many times without different outcomes..

Is http delete Idempotent?

The PUT and DELETE methods are defined to be idempotent. However, there is a caveat on DELETE. … GET, HEAD, OPTIONS and TRACE methods are defined as safe, meaning they are only intended for retrieving data. This makes them idempotent as well since multiple, identical requests will behave the same.

Why is HTTP POST not Idempotent?

Post method always results in a server state change. If the POST method was idempotent, everything sent and accepted to or from the web server would already have to exist on the server in some form to respond with the same codes and value response. For that reason, POST cannot be idempotent.

Can http delete contain body?

The latest update to the HTTP 1.1 specification (RFC 7231) explicitly permits an entity body in a DELETE request: A payload within a DELETE request message has no defined semantics; sending a payload body on a DELETE request might cause some existing implementations to reject the request.

Which is Idempotent put or post?

PUT method is idempotent. So if you send retry a request multiple times, that should be equivalent to single request modification. POST is NOT idempotent. So if you retry the request N times, you will end up having N resources with N different URIs created on server.

Is HTTP GET Idempotent?

An HTTP method is idempotent if an identical request can be made once or several times in a row with the same effect while leaving the server in the same state. … Implemented correctly, the GET , HEAD , PUT , and DELETE method are idempotent, but not the POST method. All safe methods are also idempotent.


REST or RESTful API design (Representational State Transfer) is designed to take advantage of existing protocols. While REST can be used over nearly any protocol, it usually takes advantage of HTTP when used for Web APIs. … REST API Design was defined by Dr. Roy Fielding in his 2000 doctorate dissertation.

How many HTTP methods are there?

39API developers typically only use GET, PUT, or POST, but the official HTTP Request Method registry lists 39 total HTTP verbs, each providing a method for powerful interactions.

What are the HTTP request methods?

The primary or most-commonly-used HTTP verbs (or methods, as they are properly called) are POST, GET, PUT, PATCH, and DELETE. These correspond to create, read, update, and delete (or CRUD) operations, respectively. There are a number of other verbs, too, but are utilized less frequently.

Which HTTP method is not idempotent?

If you follow REST principles in designing API, you will have automatically idempotent REST APIs for GET, PUT, DELETE, HEAD, OPTIONS and TRACE HTTP methods. Only POST APIs will not be idempotent. POST is NOT idempotent. GET , PUT , DELETE , HEAD , OPTIONS and TRACE are idempotent.

Which rest methods are idempotent?

A request method is considered “idempotent” if the intended effect on the server of multiple identical requests with that method is the same as the effect for a single such request. Of the request methods defined by this specification, PUT , DELETE , and safe request methods are idempotent.

Why put is Idempotent and patch is not?

Since PUT request (so does PATCH for that matter) updates the resource, so it can’t be cached and hence it’s not SAFE. … So multiple calls to PATCH request could end up in undesirable change in the resource state. Hence it is not IDEMPOTENT .

What are safe methods in HTTP?

An HTTP method is safe if it doesn’t alter the state of the server. In other words, a method is safe if it leads to a read-only operation. Several common HTTP methods are safe: GET , HEAD , or OPTIONS . All safe methods are also idempotent, but not all idempotent methods are safe.

Can HTTP GET have body?

Yes. In other words, any HTTP request message is allowed to contain a message body, and thus must parse messages with that in mind. Server semantics for GET, however, are restricted such that a body, if any, has no semantic meaning to the request.

What is idempotent matrix with example?

A square matrix A is said to be idempotent if A2 D A: Examples of n n idempotent matrices are the identity matrix In, the n n null matrix 0, and the matrix . 1=n/Jn, each element of which equals 1=n. As indicated by the following lemma, nn idempotent matrices are, with one exception, singular.