An API Gateway is a layer in an architecture pattern that handles many cross-cutting concerns. This article is about how we built an API Gateway in Ballerina for the WSO2 API Manager.

A back-ends-for-front-ends microservices pattern uses an API layer to preprocess data, handle calls and responses, and simplify development efforts. Here's how it all works.

In most cases we use a fraction of the external service’s functionality, so our gateway classes have public methods for just the bits we need. Each method has extensive unit specs, usually ...