> I do still have an aesthetic appreciation for "true REST", but in practice I find the fact that nobody uses it to be mainly useful in ending bikeshedding discussions. Once you understand your API isn't RESTful to begin with, there's no longer any point in arguing if 411 or 412 is the more RESTful status code to use when a user attempts to order a product without specifying a quantity.

I think I have a fundamental objection to the idea that Fielding and Fielding alone got to decide what REST is. While there hasn't been any kind of formal counterproposal, in some sense REST is what we make of it. Re: http 400 codes, I think many of us really liked the general principle of "use http semantics!" and applied that to error codes as well. That's agreeing with the principle and extending it in new ways that we like and are "truer" to the principle, even if it wasn't intended.

In my mind this is sort of analogous to talking about the relationship between linux and unix. Linux is clearly not a genetic or copyright unix, but I've seen it said before that linux is the culmination of unix principles, in some cases extended beyond what was originally envisioned in ways that are innovative and genuine improvements (io_uring perhaps?).

The REST we have today - http semantics, specific error codes, etc - may be significantly different from what Fielding may have wanted, but IMO it implements the parts that really distinguish it from the RPC world of API architecture, and I think we're generally happy with that.