Part 2. Designing and building REST APIs

In part 1, you learned what microservice APIs are and how to decompose a system into microservices. The natural questions now are, “How do you build a microservice?” and “How do you make your services talk to each other?”

We make services talk to each other using APIs, and in part 2 you learn to design and build REST APIs. Representational State Transfer (REST) is the most popular technology for building APIs, and in chapter 4 you learn all the fundamental principles of REST API design. We’ll keep the approach practical: in chapter 1, we introduced CoffeeMesh, an on-demand coffee delivery application, and in chapter 6, you learn to build CoffeeMesh’s orders and kitchen APIs using Python’s popular FastAPI and Flask frameworks.

In chapter 1 we introduced documentation-driven development and highlighted the importance of API documentation, which tells your API clients how the API works; therefore, good documentation is essential to deliver successful integrations. We document REST APIs using the OpenAPI standard, and in chapter 5 you learn step by step how to document a REST API.

Finally, in chapter 7 you learn everything you need to build microservices. You learn to implement your data layer using SQLAlchemy and to manage migrations using Alembic. You learn to structure your application using hexagonal architecture, as well as many other useful patterns and principles to encapsulate your code and maintain loose coupling between layers.

By the end of part 2 you’ll be able to design great REST APIs, produce excellent API documentation, and write highly readable and maintainable service implementations. I can’t wait to get started!