I’m looking for free or low-cost tools for building a chatbot, including A/B testing features (test different messages and see their results) or at least advanced analytics (so I can test “manually” different messages and see their individual results).
I’m not a programmer, so it should be easy to configure.
Something like http://botfuel.io/ but cheaper (free and open source would be great).

Have you looked at https://wit.ai/ ?

Yes Andrew, I’ve tried Wit.ai and several others (Api.ai, Motion.ai, Chatfuel…). They don’t have A/B testing nor the advanced analytics I need (with custom events). In the case of Wit.ai, it doesn’t have analytics at all (only logs).

I’m looking right now at https://developers.facebook.com/docs/app-events/bots-for-messenger. I plan to develop my chatbot as a Facebook bot, so that might do the trick for me. If anybody has any experience with that, I would appreciate any input, recommendation or interesting links/guides.

Miguel García What is the one key feature you think all the free ones are missing?