What does have great support? Content-Encoding works great from server -> client, but not the other way around, in my experience. That's the problem I'm discussing. It's theoretically possible to support.
the first answer to that question links to the Apache docs, it’s a one line change to add support, possibly with an additional block around it to limit scope to certain urls.
If built in support that works with one config statement isn’t “great” support, what is?
It’s not great if you want to use someone else’s API that way to save on egress bandwidth costs... that’s what. They don’t usually let me edit their Apache configs.
Apache being the only thing to support it also wouldn’t count as great. They specifically mentioned uncertainty around nginx. Have you tested any of your APIs to see if they support it?
It's going to have possible benefits for a small niche of application types. If the 3rd party services you use, accept large amounts of normally uncompressed data that is a viable candidate for transport compression, and they don't support it: that's on them. The technology is there to do it.
As for if I've "tested it". No. Because as I said: this is going to benefit only a small niche of application types. The vast majority of applications built by the vast majority of developers are going to unlikely to see any benefit at all from this type of compression, because it's not a common pattern.
Add to that, most applications are likely running in an environment where spending precious CPU cycles to compress data to send over a pipe that they're unlikely to saturate anyway, is not a winning proposition.
What doesn't have great support for Content-Encoding headers?