The first version of J.A.R.V.I.S. was released on the Messenger platform. It gained a lot of traction due to the simple nature of the bot, and the ease of contributing.
GitHub: https://github.com/swapagarwal/JARVIS-on-Messenger
Feel free to try it yourself here: https://m.me/J.A.R.V.I.S.on.Messenger