AWS AppSync is a managed service that makes it easier to build scalable APIs that connect applications to data. With AppSync, API developers can write resolvers to define the business logic that connects their AppSync GraphQL and Pub/Sub APIs to data. Developers use AppSync to interact with data sources like Amazon DynamoDB tables by writing their JavaScript resolvers that are executed on the AppSync JavaScript (APPSYNC_JS) runtime. Now, AppSync provides new functions to interact with DynamoDB tables that simplifies the developer experience in JavaScript resolvers.
Source:: Amazon AWS