If you're building one API endpoint per frontend view to avoid doing multiple API requests, your frontend and backend aren't decoupled anymore. I personally wouldn't say it's a bad thing, but if the best way to solve the issues of a decoupled frontend is to couple it to the backend again then I don't think that counts as an argument in favor of decoupled frontends.
I'm arguing in favor of coupling. Don't think front-ends should be decoupled in most situations.
There's this notion I don't see discussed often. The more distant/unstable the link is between a caller and a callee, the more coupled they should be. The closer and more reliable the link is, the less coupled they should be.
That's why when we build interfaces in a single codebase, we can let them be minimal, and let callers use loops for batch operations. But when talking over network, we build elaborate protocols and languages (e.g. SQL) to allow for more complex operations in one roundtrip.
So if one is trying to treat their backend like it's part of their front-end's codebase, that can be fetched and looped over with little regard for the many failure modes, they're going to have a bad time. The front-end to back-end is one of the most distant and unstable links we have in computing, if not _the_ most unstable. This also applies to any intermediary back-end over network.
Minimize network interactions, and shift most work into the single backend codebase for maximum reuse and reliability.
Where does the "expense" come from? You either put glue code on top of existing APIs, having almost no optimization advantages, but still having to combine data (the comment I'm responding to). Or you create new endpoints, with more code reuse in them, and more optimization. How is the latter more expensive than the former?
And if you just talk about having 1 api for 3 front-ends, aren't you then forcing your front-ends to contain a ton of business logic to figure out how and what to display based on your API? You could've just given them what they need, but instead they're forced to weave together some insane tapestry from all kinds of "generic" endpoints you gave them? Isn't it expensive to maintain those front-ends?
> but still having to combine data (the comment I'm responding to).
The GP frames the problem as merely avoiding round trips. You introduced the idea of eliminating redundant database calls on the back end. In that scenario, you absolutely have the right idea.
