Notes on what I've learned about Appsync


What is AppSync?

AppSync is a cloud-based data synchronization service provided by AWS. Its key features and functions include:

  • Data Sources: AppSync can integrate with various data sources, allowing access to a wide range of data, from AWS databases to external APIs.

  • GraphQL: Using GraphQL, clients can efficiently retrieve the necessary data, with the ability to customize request and response formats.

  • Real-time Data Synchronization: When data changes occur, AppSync sends real-time notifications to clients, enabling the development of real-time applications.

  • Security and Authentication: AppSync supports various authentication methods to ensure secure access to data.

  • Offline Data Synchronization: For mobile applications, AppSync enables data synchronization even when devices are offline.

AppSync is a powerful tool for meeting the data synchronization and real-time communication requirements in cloud-based application development.

Now, let's delve a bit deeper into some of these explanations.

Data Sources

AppSync can retrieve data from multiple databases, making it convenient for integrating different data sources, including various AWS database services (e.g., DynamoDB, RDS, Elasticsearch), and external APIs (REST, GraphQL, HTTP).

This is particularly useful when applications need to gather information from multiple data sources and present it to clients in a unified manner. For example, you can retrieve user profile information from DynamoDB and product information from an external REST API, then provide them to clients in a single GraphQL query.


Here are some advantages of using GraphQL with AppSync:

  • Flexible Data Retrieval: Clients can specify the data they need in queries, preventing unnecessary data retrieval and reducing waste.

  • Single Endpoint: GraphQL APIs are typically provided through a single endpoint, eliminating the need for multiple endpoints as seen in RESTful APIs. This simplifies API endpoint management and streamlines client requests.

  • Type System: GraphQL has a type system that allows explicit definition of data types and their fields, ensuring safety.

  • Real-time Data: It supports real-time data requirements with bidirectional communication. Ideal for implementing chat functionality.

  • Custom Resolvers: In a GraphQL server, you can define custom resolvers for each field's data retrieval logic. It's also compatible with JavaScript, making it very convenient.

Security and Authentication

As an example of security features, AppSync can leverage AWS Cognito's authentication capabilities, making it easy to implement authentication-related functionalities.

Benefits of Using AppSync

  • No need to manage HTTP communication with GET, POST, PUT, DELETE, PATCH like restTemplate.
  • Query requests allow data retrieval from multiple data sources.
  • Bidirectional communication is possible, ideal for building chat applications.
  • Integration with AWS services like Cognito, EC2, DynamoDB, RDS for improved security and data management.
  • AppSync resolvers are compatible with JavaScript, enabling both back-end and front-end development.


AppSync makes it easy to create microservices conveniently. It's a powerful tool.

Seeing is believing. (This is old Japanese saying.)
I plan to use it in my future personal projects to ensure that I retain what I've learned.