Just stumbled upon this thread. Nice summary, @georgecollier . It seems to reiterate the basic strategy I outlined several years ago (and which I still use).
Having said that, I’ll be implementing a “relay” approach (not unlike this Cloudflare example) in an upcoming project. I made that decision based on the anticipated higher volume, higher dollar amounts, and higher risk profile of the transactions.
Anyway, it’s a shame Bubble doesn’t provide access to the raw request data (similar to the raw body text feature of API calls). It would make things simpler and easier. I like simple. 