JMAP for Calendars, Contacts and Files Now in Stalwart

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.

> binary protocol

Email was never a binary protocol. Notoriously so, it's why MIME types and MIME encodings get so complicated.

Most of the "old internet" protocols (email, FTP, even HTTP itself) were bootstrapped on top of built-mostly-for-plaintext Telnet. HTTP as the new telnet has a bunch of improvements when it comes to binary data, request/response-based data flows, and some other considerations. HTTP/3 is even inherently a binary protocol, it's lack of "telnet-compatibility" one of the concerns about switching the majority of the web to it.

vCard/vCal/iCard/iCal were also deeply "plaintext formats". JSON is an improvement because it is more structured, even more efficient, than those predecessors. JSON may not look efficient, but it compresses extremely well and can be quite efficient in gzip and Brotli streams.

I feel like "JSON over HTTP" is a subtle improvement over "custom text formats over telnet", even if it doesn't sound like "binary protocol efficiency" at first glance. Especially as HTTP/3 pushes HTTP more efficient and more "binary", and arguably "more fundamental/basic" with HTTP/3 even taking over more roles in the TCP/UDP layer of the internet stack. (Telnet would never try to replace TCP.) HTTP isn't the worst bootstrap layer the internet could use to build new protocols and apps on top of. Sure, it would be neat to see more variety and experiments outside of the HTTP stack, too, but HTTP is too useful at this point not to build a bunch of things on top of it instead of as their own from-scratch protocol.

> Most of the "old internet" protocols (email, FTP, even HTTP itself) were bootstrapped on top of built-mostly-for-plaintext Telnet.

That's just not true. Telnet and SMTP are built on top of TCP. They live on the same layer. They were originally both protocols that transmitted data with printable ascii, hence why they look similar. There are many other protocols like Telnet and SMTP that worked like that, auch as nntp, irc, and yes, even http.

I think that the point is this: You could literally use a telnet client to talk to all of those servers and it was considered a good thing, maybe even an essential feature. So protocol design was somehow influenced by the need to be fully plain text ASCII streams (and maybe that other options weren't adequately explored due to this restriction)