Understanding the OpenAPI Specification

OpenAPI Specification provides a standardized way to describe REST APIs. This chapter introduces OpenAPI’s fundamentals: its history, purpose, and structure. Through our Magic Items store example, you’ll learn how to structure an OpenAPI document and define its core components, from basic metadata to endpoints, parameters, responses, and security definitions.

We will cover the following main topics:

• The origins and purpose of OpenAPI
• Designing REST APIs with OpenAPI Specification
• The structure of OpenAPI Specification

By the end of this chapter, you will have a clear understanding of how to effectively describe all key aspects of your API’s design and formalize them using the OpenAPI Specification format. You will also gain insight into the structure of your API and learn how to avoid common pitfalls associated with each element.