To create a REST API using MongoDB, start by installing and populating MongoDB with your data. Then, create the logic to interact with your data, which may involve using an API framework or driver. Next, define the API name, description, and logo, and specify the path to a specific endpoint and available parameters. Choose API plans and pricing, and provide more detailed documentation about your API. Finally, use the RapidAPI Provider Dashboard to create the API, specifying the API endpoints, available parameters, and pricing plans. Throughout this process, ensure that you validate user input and handle errors properly, and consider how to handle API calls for testing, development, and scalability.