Vonage uses OpenAPI to describe its APIs and has created a Postman Collection for easy exploration and evaluation. To use this collection, you need a Vonage API account with an API Key and Secret, as well as a virtual phone number. Postman supports environment, global, and collection-level variables, which enable dynamic filling of parameter values, making tasks smoother and less painful. Chaining requests can also be used to handle multi-step prerequisites, allowing for scripting in JavaScript using the Pre-Request Script or Tests area. The Request Body section provides a concise example of how to use these features to make a text-to-speech voice call. By sharing the collection, others can easily fill in missing variable values and press the Send button.