While JMAP seems to scratch every itch of a sucker for proper web API design, I’m wondering if the design space for new protocols should really be constrained to layers on top of HTTP. Is there really any new-ish binary protocol these days?
Stuff like file sharing or groupware, mail, calendars, and so on—these things could be a lot more efficient and don’t really need the overhead of JSON as the message interchange format, IMHO. Then again, a lot of solid thinking went into these things, so there probably are a lot of good reasons that I’m not aware of.
Still, it’s an interesting space, I think.