# What is Amazon AppSync?
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Amazon AppSync enables developers to connect their applications and services to data and events with secure, serverless and high-performing GraphQL and Pub/Sub APIs. You can do the following with Amazon AppSync:
+ Access data from one or more data sources from a single GraphQL API endpoint.
+ Combine multiple source GraphQL APIs into a single, merged GraphQL API.
+ Publish real-time data updates to your applications.
+ Leverage built-in security, monitoring, logging, and tracing, with optional caching for low latency.
+ Only pay for API requests and any real-time messages that are delivered.

**Important**  
As of Mar 13, 2025, you can build a real-time PubSub API powered by WebSockets using Amazon AppSync Events. For more information, see [Publish events via WebSocket](https://docs.amazonaws.cn/appsync/latest/eventapi/publish-websocket.html) in the *Amazon AppSync Events Developer Guide*.

**Topics**
+ [Amazon AppSync features](#appsync-feature-overview)
+ [Are you a first-time Amazon AppSync user?](#first-time-user)
+ [Related services](#related-services)
+ [Pricing for Amazon AppSync](#pricing-for-appsync)

## Amazon AppSync features
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+ Simplified data access and querying, powered by GraphQL
+ Serverless WebSockets for GraphQL subscriptions and pub/sub channels
+ Server-side caching to make data available in high speed in-memory caches for low latency
+ JavaScript and TypeScript support to write business logic
+ Enterprise security with Private APIs to restrict API access and integration with Amazon WAF
+ Built in authorization controls, with support for API keys, IAM, Amazon Cognito, OpenID Connect providers, and Lambda authorization for custom logic.
+ Merged APIs to support federated use cases

For more details about each of these capabilities, see [Amazon AppSync features](https://www.amazonaws.cn/appsync/product-details). 

## Are you a first-time Amazon AppSync user?
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We recommend that first-time Amazon AppSync users begin by reading the following sections:
+ If you're unfamiliar with GraphQL, see the [Getting started: Creating your first GraphQL API in Amazon AppSync](quickstart.md).
+ If you're building applications that consume GraphQL APIs, see [Building a client application using Amplify client](building-a-client-app.md) and [Using subscriptions for real-time data applications in Amazon AppSync](aws-appsync-real-time-data.md).
+ If you're looking for GraphQL resolver information, see the following:

  JavaScript/TypeScript
  + [Resolver tutorials (JavaScript)](https://docs.amazonaws.cn/appsync/latest/devguide/tutorials-js.html)
  + [Resolver reference (JavaScript)](https://docs.amazonaws.cn/appsync/latest/devguide/resolver-reference-js-version.html)

  VTL
  + [Resolver tutorials (VTL)](https://docs.amazonaws.cn/appsync/latest/devguide/tutorials.html)
  + [Amazon AppSync resolver mapping template reference (VTL)](resolver-mapping-template-reference.md)
+ If you're looking for Amazon AppSync example projects, updates, and more, see the [AppSync blog](https://aws.amazon.com/blogs/mobile/category/mobile-services/aws-appsync/).

## Related services
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If you're building a web or mobile app from the ground up, consider using [Amazon Amplify](https://www.amazonaws.cn/amplify/). Amplify leverages Amazon AppSync and other Amazon services to help you build more robust, powerful web and mobile apps with less work.

## Pricing for Amazon AppSync
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Amazon AppSync is priced based on millions of requests and updates. Caching costs an additional fee. For more information, see [Amazon AppSync pricing](https://www.amazonaws.cn/appsync/pricing/).

 The following lists the exceptions to general Amazon AppSync pricing:
+ Requests are not charged for authorization and authentication failures.
+ Calls to methods that require API keys are not charged when API keys are missing or invalid.