[Silhouette]

You say that, but it seems to me that one of the key factors in Stripe's early success was being developer-friendly in a way that no other card payment service was at the time. Part of that in turn was coming up with a good API and clean integrations at the JS level, and then documenting all of that so well that many other sites have since adopted the same presentation style for their own documentation pages.

Compare that with the obvious established competitor, PayPal, who have made a fortune from letting people collect money by putting a simple button on their site with just the slightest level of integration needed, but whose APIs and documentation have changed over time and yet remained consistently awful for developers wanting to do more substantial integrations to meet more demanding requirements.