The easiest way to understand the difference is:
- OpenAPI = Specification
- Swagger = Tools for implementing the specification
The OpenAPI is the official name of the specification. The development of the specification is fostered by the OpenAPI Initiative, which involves more the 30 organizations from different areas of the tech world — including Microsoft, Google, IBM, and CapitalOne. Smartbear Software, which is the company that leads the development of the Swagger tools, is also a member of the OpenAPI Initiative, helping lead the evolution of the specification.
Swagger is the name associated with some of the most well-known, and widely used tools for implementing the OpenAPI specification. The Swagger toolset includes a mix of open source, free, and commercial tools, which can be used at different stages of the API lifecycle.
