The Swagger Editor (https://swagger.io/tools/swagger-editor/) is a web application that you can use to edit OpenAPI definition files. You can run the web application on-premises, or you can use an online sample version at https://editor.swagger.io.

The Swagger Editor allows you to open a Swagger file from your computer or an external API. I downloaded the swagger.json file from the GiveNTake API and imported it into the Swagger Editor, as shown here:

With the OpenAPI definitions loaded, you can click on the Generate Client menu item to select the language you wish to generate for the client:

After code generation is complete, a ZIP file will be downloaded to your machine containing the code that you can now use in your application.