Interview

Roy Fielding on Versioning, Hypermedia, and REST

I talk about it because the initial reaction to using REST for machine-to-machine interaction is almost always of the form "we don’t see a reason to bother with hypermedia — it just slows down the interactions, as opposed to the client knowing directly what to send." The rationale behind decoupling for evolvability is simply not apparent to developers who think they are working towards a modest goal, like "works next week" or "we’ll fix it in the next release".

If developers can conceive of their systems being used for a much longer time, then we can escape their own preconceptions about how it will need to change over time. We can then work back from decades to years (how long until you don’t know your users?) or even months (how long until you’ve lost control over client deployment?).