OpenAPI, formerly known as Swagger, is a specification for building and documenting APIs. This talk is about the significance of OpenAPI in the world of API development and when a lot of people suddenly realised its importance for modern-day software development. We'll explore the technical aspects, wider ecosystem, and future of OpenAPI in the world of API development and discuss the benefits of OpenAPI, its role in API documentation, and its importance in building robust and scalable APIs used by leading companies (e.g. OpenAI).