GraphOS allows developers to consolidate data from multiple sources into a unified view using Apollo Federation, enabling seamless access to product and review data. By creating separate subgraphs for products and reviews, teams can manage different portions of the schema while maintaining a single supergraph schema that exposes different views to different API consumers. Using Apollo Studio's Contracts feature, developers can configure an endpoint for third-party partners to query, exposing limited partner schemas with specific fields and tags to control access to internal data. This approach enables the creation of a retail supergraph that powers modern retail applications while maintaining flexibility and scalability.