Difference between RASA restful interfaces and Custom Connector

@Vincent could you give me a clue for the difference between RASA restful interfaces in following link :Rasa Open Source HTTP API

and Customer connector : Custom Connectors

For integrating RASA in a platform as an external ecosystem ??

It’s a matter of abstraction. You could interface with REST but at some point you might end up writing a lot of boilerplate. Especially if you’re dealing with a service that already has a python API (like Discord) then it makes sense to use the custom-connector API. If you’re 100% dealing with a front-end on the web however, it seems preferable to keep it REST-y.