Many years ago as a young developer I read Fielding's dissertation, Fowler's writings on the Richardson Maturity Model and even a book (don't remember the title) on the topic. Then I spent the next dozen years creating, reading, updating and deleting JSON APIs.

Problem Details (RFC 9457) are useful and have made an occasional appearance, but actual hypermedia driven APIs with custom media types seem to be non-existent outside of example blog posts. It's much more common to instead see APIs overload lesser-used HTTP status codes with their own domain-specific meanings. But if I'm being honest, this sort of protocol crime almost never caused an actual problem in practice.

The advocacy for "true REST" is missing a compelling argument and useful example of why it would actually be an improvement. Despite its prominence, for over 20 years almost nobody has used this approach. Why is that?

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. (Spoiler: neither is correct) You simply send a 400 with Problem Details and call it a day. Ironically, this indifference may make your API just a little bit more RESTful.

I had flashbacks to when I first started making web apps. I used to care so very much about this. I haven’t thought about capital REST in years.

Edit: a few minutes after I wrote that I had the thought, what if this is someone else’s arc with AI code. A lot of people seem to care a whole awful lot right now. A decade time horizon is interesting to think about.

> 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.

> Despite its prominence, for over 20 years almost nobody has used this approach. Why is that?

There is one highly successful use of REST: the World Wide Web.

The Web/Web browsers are driven from hypermedia. (This is circular, as Fielding was looking at the web when making his dissertation.)

Granted, Web browsers stand alone as an application with extreme flexibility.

So REST is both highly common and very rare, depending on how you count.