The API economy benefits startups and enterprises by fostering innovation, enhancing collaboration, and enabling scalability. By providing APIs, businesses can share their services and data with external developers, leading to the creation of new applications and integrations. This can significantly reduce time-to-market for new products and features, giving startups a competitive edge. Moreover, established enterprises can leverage external talent to enhance their offerings without extensive internal development costs. The modular nature of APIs also allows companies to adapt and expand, facilitating growth in response to market demands and user needs.