Stripe + Fathom purchase tracking

I implemented purchase tracking from Stripe with Google Analytics via Zapier integration.
However, want to track purchase Goals in Fathom.

Anyone successful in doing that?
I researched Webhooks - but there are no “stock” membership Webhooks.

  1. Should hack into ghost’s code to find stripe callback and send params into webpage, from which data is sent via JS to Fathom?

or is there a beautiful solution