Stripe API is great. How they do it is available online. Why was no company able to replicate it? The APIs are only the tip of the iceberg. Here are the 7 main reasons that make the Stripe API so hard to replicate:
1 - Crafting from the early days
The first public API took 1 year and was the 3rd rewrite. Even in a pre-product and pre-revenue startup. With a few people team:
2 - Scaling with product orientation
Stripe hired the first PM at 150 people, 5 years after founding. Engineers have a strong product mindset. They hire a lot of engineers with product experience.
3 - Leveraging proven models
They use the process created at Amazon of working backward from the press release. By the time they start building the API: docs, FAQs, UI mockups, and a lot more is already built.
4 - A culture that can handle failure
In the North Star podcast by David Perell, patio11 mentions an example. If 8 people work on a project for 6 months, and the feedback is bad, they will throw it away:
5 - Beyond documentation or API design
The design process for the API is like any product with great UX. Many iterations of mockups, user interviews, usability tests, dogfooding, rewrites, and so on. This means much more design vs building time.
6 - It's more about culture and trade-offs
Does your culture support throw months of work away? Are you willing to postpone launch dates to improve quality? Can you afford to put 10x more time into your API development time compared to today?
7 - Doing things like Stripe is good anyways
Adding things Stripe does to your documentation & API design is a nice thing. It's been through a strong process before it got released, and will probably work. But don't expect to reach Stripe level quality only by doing this.