AWS AppSync uses GraphQL, a data language that enables client apps to fetch, change and subscribe to data from servers. In a GraphQL query, the client specifies how the data is to be structured when it is returned by the server. This makes it possible for the client to query only for the data it needs, in the format that it needs it in. GraphQL also includes a feature called “introspection” which lets new developers on a project discover the data available without requiring knowledge of the backend.
Real-time data access and updates
AWS AppSync lets you specify which portions of your data should be available in a real-time manner using GraphQL Subscriptions. GraphQL Subscriptions are simple statements in the application code that tell the service what data it should be updated in real-time.
Offline data synchronization
AWS AppSync supports an offline programming model where application data is not only available offline, but users can add and update data as well. When the device is offline, the application UI will be automatically updated with the offline data. AppSync lets you can define how data is cached offline as well as how AppSync should manage the cache updates under different network conditions.
Data querying, filtering, and search in apps
AWS AppSync gives client applications the ability to specify data requirements with GraphQL so that only the needed data is fetched, allowing for both server and client filtering. Since AWS AppSync supports AWS Lambda, Amazon DynamoDB and Amazon Elasticsearch, the GraphQL operations can be simple lookups, complex queries & mappings, full text searches, fuzzy/keyword searches or geo lookups.
Enterprise security and fine-grained access control
AWS AppSync allows several levels of data access and authorization depending on the needs of an application. Simple access can be protected by a key and more restrictive permission can be done with AWS Identity and Access Management using Roles. Additionally, AWS AppSync integrates with Amazon Cognito User Pools for email and password functionality, social providers (Facebook, Google+, and Login with Amazon), and enterprise federation with SAML. Customers can use the Group functionality for logical organization of users and roles as well as OAuth features for application access.