Real-Time Application Patterns with AWS AppSync Events

Real-Time Use Cases

• Event Broadcasting: Sending real-time updates to many connected clients

  • Example: Updating fans on a sports game-changing touchdown or inventory availability on an e-commerce website

• Real-Time Collaboration: Enabling communication and interaction between two or more clients

  • Example: Multi-turn gameplay where players strategize and feed off each other's moves, or a call center where agents need to see ticket updates in real-time

Challenges with Existing Solutions

• Polling: Clients frequently checking for updates, leading to increased latency, unnecessary resource utilization, and scalability challenges
• WebSockets: Complexity in managing connections and fan-out of messages, requiring custom backend code

AWS AppSync Events

• A fully managed pub/sub service for building real-time experiences at scale
• Reduces operational overhead by handling connection management, message fan-out, authentication, and other enterprise features
• Allows publishers (application clients or backend services) to publish events over an HTTP POST API
• Subscribers (application clients or backend services) connect over a WebSocket to receive updates in real-time

Key Features

• Namespaces and Channels: Namespaces provide centralized configuration and behaviors, while channels are ephemeral and created on-the-fly
• Event Handlers: JavaScript functions that can be used for event enrichment, schema validation, and filtering
• Authorization: Support for various modes like Amazon Cognito, OpenID Connect, AWS Lambda, API keys, and IAM
• Scalability and Performance: Default quotas of 1 million messages per second outbound and 10,000 messages per second inbound, with no limit on the number of connections
• Cost-Effective: Serverless, pay-per-use pricing at $1 per million API operations, with a free tier

Real-World Architecture Patterns

1. Event Broadcast:

   • One or more publishers (backend services) broadcasting events to many connected clients (subscribers)
   • Example: Sports scores and stats, inventory availability, or real-time voting

2. Collaborative Patterns:

   • Multiple publishers (application clients) interacting with a set of subscribers in a collaborative fashion
   • Example: Group chat, collaborative document editing, support ticket updates, or turn-based gameplay

Advanced Patterns

• Event Persistence: Persisting events to a data store to allow clients to query for the last update or replay messages
• Event Order: Adding timestamps or other metadata to events to enable clients to reason about the order of events

Future Enhancements

• Private APIs: Support for deploying AppSync Events APIs within a VPC
• WebSocket Publish: Adding the ability to publish over WebSocket, in addition to the current HTTP POST
• Lambda Integration: Allowing event handlers to be written in other languages and access external resources
• Built-in Data Sources: Integrating with services like DynamoDB, Aurora, OpenSearch, and Amazon Bedrock (generative AI) for event handling
• Event Persistence and Presence Detection: Providing built-in options for event persistence, ordering, and presence detection

Get Started

• Explore the AppSync Events documentation
• Attend upcoming sessions and workshops related to AppSync Events
• Provide feedback through the surveys to help shape the future roadmap