By the way if you're interested in experimenting more broadly outside of a stripe integration I wrote the quickstarts for Optimizely Full Stack which use a discount example, feel free to ask me questions about how it works :) (we have a free plan too) https://docs.developers.optimizely.com/full-stack/docs/javas...
That's a really neat quickstart! We actually allow to go outside of the Stripe integration and have an API to ping purchases here (https://doc.corrily.com/openapi/reference/operation/setSucce...)... But I wonder how to make it more user friendly. We did get a js SDK, but it wasn't very neat. Do you have any thought on what UX would make the most sense?