List of Important Methods

Before we discuss the HTTP methods, let's review three aspects of HTTP verbs:

• Idempotency: Idempotency is an important concept in HTTP calls. In idempotent requests, you can change the server-side state (however, only once). That is, if you make multiple idempotent requests to the server, the net effect will be as if you have done one request.

• Safety: Safe requests simply do not cause any side effects. They are only used to retrieve data. By side effects, we refer to any persistent changes in memory or database or any other external system. Registering a user is a side effect. Making a money transfer is a side effect. But viewing user information is not a side effect.
• Cacheablity: Server or client or proxies can cache the responses for the requests.

In the preceding table, we can see that the GET method is the only safe method. And that's why, for example, search engines like Google only use GET methods to scan our side. Adhering to this standard makes sure nothing is changed during a search engine scan.