AWS AppSync is a fully managed GraphQL service that makes it easy to build data-driven apps and services by enabling you to execute GraphQL queries on your data.

In this article, we will cover:

What is AWS AppSync?

How to build real-time and offline apps with AppSync

Using GraphQL with AppSync

Integrating AppSync with AWS Lambda and DynamoDB

What is AWS AppSync?

AWS AppSync is a managed cloud service that enables you to execute GraphQL queries on your data. It supports real-time data synchronization across mobile devices and web applications.

Some key features of AWS AppSync are:

• Fully managed GraphQL API - AppSync manages the infrastructure required to run a GraphQL API, including caching, logging, and monitoring.

• Real-time data synchronization - AppSync can push data changes in real time to clients using websockets.

• Offline data support - AppSync syncs data changes made by mobile clients while they are offline, allowing for an offline-first experience.

• Integrations - AppSync integrates with various AWS services like DynamoDB, Lambda, Elasticsearch, and more.

• Security - AppSync provides features like API keys, IAM roles, and access control lists for secure access.

• Schema versioning - AppSync allows versioning your GraphQL schema and provides a transition pathway between versions.

Building real-time and offline apps with AppSync

You can build real-time and offline-enabled web and mobile apps using AppSync as the backend. Here are the basic steps:

1. Define your GraphQL schema - This defines the data and operations your app needs.

2. Configure data sources - Connect AppSync to your data sources like DynamoDB, Lambda, etc.

3. Implement resolvers - Write the business logic to fetch data from the data sources and return the result.

4. Deploy the API - Deploy the GraphQL API to AppSync.

5. Integrate AppSync clients - Integrate the AppSync API client libraries in your web/mobile apps.

6. Enable subscriptions - Enable subscriptions to receive real-time data updates from AppSync.

7. Handle offline mutations - Implement an offline mutation store to sync local mutations when back online.

Using GraphQL with AppSync

AppSync uses GraphQL to define your API schema and queries. Some key benefits of using GraphQL with AppSync are:

• Fetch exact data required - Clients can fetch the specific fields they need using GraphQL queries.

• Support for mutations - GraphQL mutations allow clients to modify data.

• Strongly typed - The GraphQL schema provides a strong contract between clients and the API.

• Flexible - The GraphQL schema can evolve independently of clients.

Integrating AppSync with Lambda and DynamoDB

Some common integrations with AppSync include:

• AWS Lambda - Use Lambda functions as resolvers to fetch/modify data in various AWS services.

• Amazon DynamoDB - Connect DynamoDB tables as data sources and use them in your resolvers.

• AWS Amplify - The Amplify JavaScript library makes it easy to integrate AppSync in web/mobile apps.

• AWS Cognito - Use Cognito for user management and authorization with AppSync.