How does the client know when it's time to clear the cache for a specific resource?

Question

RESTful API

Let's say we have a client and a server. Everything is done in RESTful architecture. The client caches resources received from the server. But we know that as soon as the data changes on the server, the client must clear the cache.
And so, the question. In what ways does the server communicate to the client, or does the client find out from the server that the data has changed?

Answer 1

Either add the version number to the url or use etag .