This paper describes a layered HTTP infrastructure designed to support web-based APIs in a standard, secure, scalable, and highly available fashion. The efforts described here are based on the observation that large scale distributed systems exhibit greater robustness, flexibility, and extensibility when they are conceived, built, and operated as a set of small independent but interconnected components. Leveraging the power of DNS routing and the HTTP protocol, we have built a platform that makes it easy for engineering teams within the organization to expose their services to other teams as HTTP APIs, and in turn to build their solutions based on other teams' APIs. The adoption of the API platform has reduced duplicate efforts, increased the overall security of our systems, provided greater control and visibility of how components are being used, and ultimately helped us innovate more quickly.