Resolver tutorials (VTL) - AWS AppSync

Resolver tutorials (VTL)


We now primarily support the APPSYNC_JS runtime and its documentation. Please consider using the APPSYNC_JS runtime and its guides here.

Data sources and resolvers are how AWS AppSync translates GraphQL requests and fetches information from your AWS resources. AWS AppSync has support for automatic provisioning and connections with certain data source types. AWS AppSync supports AWS Lambda, Amazon DynamoDB, relational databases (Amazon Aurora Serverless), Amazon OpenSearch Service, and HTTP endpoints as data sources. You can use a GraphQL API with your existing AWS resources or build data sources and resolvers. This section takes you through this process in a series of tutorials for better understanding how the details work and tuning options.

AWS AppSync uses mapping templates written in Apache Velocity Template Language (VTL) for resolvers. For more information about using mapping templates, see the Resolver mapping template reference. More information about working with VTL is available in the Resolver mapping template programming guide.

AWS AppSync supports the automatic provisioning of DynamoDB tables from a GraphQL schema as described in Provision from schema (optional) and Launch a sample schema. You can also import from an existing DynamoDB table which will create schema and connect resolvers. This is outlined in Import from Amazon DynamoDB (optional).