Implementing a unified e-commerce checkout with GraphQL can help elevate modern retail apps by providing a frictionless experience for shoppers. Apollo GraphOS, an end-to-end supergraph platform, unifies all cloud data and services into a single connected GraphQL schema, allowing developers to save time rewriting code across customer-facing apps and focus on shipping product features. By designing a digital cart with GraphOS, developers can create a focused operation to perform, giving each client team the ability to focus on creating the best UX flow instead of independently writing duplicate logic. The schema includes mutations for adding and removing items from the cart, as well as checkout actions, allowing users to set up their own cart and complete transactions in a standardized way. By unifying checkout experiences across client apps, retailers can capitalize on every revenue opportunity and improve customer satisfaction.