Swagger is a suite of tools for API developers from SmartBear Software and a former specification upon which the OpenAPI Specification is based.
The Swagger API project was created in 2011 by Tony Tam, technical co-founder of the dictionary site Wordnik.

Swagger's open-source tooling usage can be broken up into different use cases: development, interaction with APIs, and documentation.

When creating APIs, Swagger tooling may be used to automatically generate an Open API document based on the code itself.
This embeds the API description in the source code of a project and is informally called code-first or bottom-up API development.

Using the Swagger Codegen project, end users generate client SDKs directly from the OpenAPI document, reducing the need for human-generated client code.
As of August 2017, the Swagger Codegen project supported over 50 different languages and formats for client SDK generation.

When described by an OpenAPI document, Swagger open-source tooling may be used to interact directly with the API through the Swagger UI.

Official Website :- https://swagger.io/
Open API :- https://openapis.org/