> The vision of API that is self discoverable and that works with a generic client is not practical in most cases. [..] Fielding's paper doesn't provide a complete recipe for building self-discoverable APIs. It is an architecture, but the details of how clients should really discover the endpoints and determine what these endpoints are doing is left out of the paper. To make truly discoverable API you need to specify protocol for endpoints discovery, operations descriptions, help messages etc. Then you need clients that understand your specification, so it is not really a generic client
You said what I've thought about REST better than I could have put it.
A true implementation of a REST client is simply not possible. Any client needs to know what all those URLs are going to do. If you suddenly add a new action (like /cansofspam/123/frobnicate), a client won't know what to do with it. The client will need to be updated to add frobnication functionality, or else it just ignores it. At best, it could present a "Frobnicate" button.
This really is why nobody has implemented a REST server or client that actually conforms to Fielding's paper. It's just not realistic to have a client that can truly self-discover an API without being written to know what APIs to expect.
> A true implementation of a REST client is simply not possible
Sure it is, it's just not very interesting to a programmer. It's the browser. That's why there was no need talk about client implementations. And why it's hypermedia driven. It's implicit in the description that it's meant to be discoverable by humans.
AirBnb rediscovered REST when they implemented their Server Driven UI Platform. Once you strip away all the minutiae about resources and URIs the fundamental idea of HATEOS is ship the whole UI from the server and have the client be generic (the browser). Now you can't have the problem where the frontend gets desynced with the backend.
> It's the browser.
This cannot be overstated.
I'm watching with some interest to see if the LLM/MCP crowd gradually reinvents REST principles. LLMs are the only software we have invented yet which is smart enough to use a REST interface.