A managed service for building APIs that let clients request exactly the data they need in a single query, rather than making multiple requests to different endpoints. Like ordering from a custom menu where you pick exactly what you want, instead of choosing from fixed meal combos.
A mobile app team uses AWS AppSync to build a GraphQL API that lets their iOS and Android apps fetch user profiles, posts, and comments in a single query — reducing network calls by 80% compared to their old REST API and dramatically improving load times on slow connections.