JavaScript developers can now tap into Amazon's vast product listings and reviews using APIs, allowing them to create apps that leverage this data to enhance their own products or services. The tutorial uses RapidAPI as an intermediary, providing access to Amazon Product/Reviews/Keywords API endpoints for product search and review data. The code is written in JavaScript, with asynchronous functions used to fetch data from the API and display it on a user-friendly interface. With minimal lines of code, the app enables users to search products by keyword, view reviews, and even show more details about each product's rating and price. By utilizing Amazon APIs, developers can build innovative apps that tap into this vast data repository, enhancing their own offerings and providing valuable insights to customers.