The ESP32 comes with stupid amounts of standard library, including (multiple) crypto libraries and Expat for XML. Also it's quite optimized to do internet stuff while clocking at 240 MHz, I'm pretty sure that a bit of XMPP should be doable for it. Also two cores ^^
The standard lib even includes protobuf, if you want to OMEMO :P
Syndace, COM8, which sytems software do you run on the ESP32?
(I have no experience with the ESP32 and maybe that's a stupid question because there is only one)
I run ESP-IDF in my current project, which is the somewhat official toolchain by the producer. Most people tend to use the Arduino toolchain.
And that's all the toolchains I know of.
Oh and the OS which runs when using ESP-IDF is FreeRTOS, not sure what OS Arduino flashes.