A simple and unopionated boilerplate messenger bot built with NodeJS and web requests + MongoDB support baked in.
Simply modify the API and app keys you can access at Facebook's Messenger section of their dev site.
If you want to access an external API, simply modify the URL variable and set it to send the correct data. You can use regex or simply cutting a substring to parse for data. My example API use calls a fictitous web service to send location information for a given date and time to the user.
This is fully extensible, and you can even build a full website on top of this as ExpressJS is built in.