how many email providers are there? 40-50? Do you really are going to do a custom integration for every app?

You might better stop developing a lot of custom integrations. It's much better for all of us to have webhooks and build a flow with integromat.

We don't have to wait for the custom integration of our favorite app and you don't have to stop your development for doing so many integrations... A webhook + an Integromat tutorial and a fast, easy and happy setup :-)