A REST client needs little to no prior knowledge about how to interact with an application or server beyond a generic understanding of hypermedia.
[2] A user-agent makes an HTTP request to a REST API through an entry point URL.
A client does not need to understand every media type and communication mechanism offered by the server.
The ability to understand new media types may be acquired at run-time through "code-on-demand" provided to the client by the server.
[2] The HATEOAS constraint is an essential part of the "uniform interface" feature of REST, as defined in Roy Fielding's doctoral dissertation.