For data partially available in databases, retrieve the data either directly from AWS AppSync, or by using Lambda functions as proxy resolvers to your databases. For data partially available in external sources, use Lambda resolvers to fetch the data by invoking remote HTTP APIs. To improve your API’s performance, enable server-side caching on AWS AppSync. Other parties using AWS can replicate this architecture in their domains, also allowing clients to query their APIs using GraphQL, and composing the results with internal and external resolvers – including your domain’s GraphQL API. Parties that don’t AWS can also expose their domains with GraphQL APIs built with other technologies. This provides a seamless experience to clients, while composing query results with data sets resolved from multiple external APIs. To retrieve large datasets, clients can subscribe to AWS Data Exchange instead.
