Integromat works very much like Zapier. I haven’t had a chance to post a dedicated example, but if you configure Integromat (I guess now Make.com? Haven’t followed this) actions (or whatever they call them) to be triggered by a webhook, you can use the exact example action in the Zapier guide that shows how to post to a webhook, just with the URL Integromat provides.
Requires you understand some basic Javascript/JSON to format the params you want, but same process.
(May also be possible to email into Integromat to trigger things using Drafts mail actions, have not explored that)