Designing APIs with OAS
You can directly start coding the API; however, this approach leads to many issues, such as frequent modifications, difficulty in API management, and difficulty in reviews specifically led by non-technical domain teams. Therefore, you should use the design-first approach.
The first question that comes to mind is, how can we design REST APIs? You learned in Chapter 1, RESTful Web Service Fundamentals, that there is no existing standard to govern REST API implementation. OAS was introduced to solve at least the aspects of the REST API’s specification and description. It allows you to write REST APIs in the YAML Ain’t Markup Language (YAML) or JavaScript Object Notation (JSON) markup languages.
We’ll use version 3.0 of OAS (https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.3.md) to implement the e-commerce app REST API. We’ll use YAML (pronounced as yamel, rhyming with camel), which is cleaner and easier to read...
