API-first companies are a subset of Software-as-a-Service (SaaS) companies, with a few key distinguishing features:

Strong API-first businesses sit in this sweet spot: they provide mission critical but non-core functionality to their customers, like accepting payments, providing cloud security, or sending communications to customers.

APIs create an environment where anybody who wants to develop on top of their platforms can do so. No need to send you a formal request, just take those APIs and innovate. Then, if someone builds a great new service or capability, we'll work out a commercial licensing agreement so that everyone makes money.

- API-driven architecture is maturing as a paradigm and enabling more communication between applications across value chains.