advanced~3h

Design a Chat Application on AWS

A worked system-design example for a real-time messaging app on AWS — API Gateway WebSockets for persistent connections, DynamoDB for message history, and the fan-out challenge of delivering a message to potentially many active connections.

0
Subtopics

🎓 Learning objectives

  • Explain why WebSockets (not plain HTTP polling) are needed for real-time chat, and how API Gateway supports them
  • Design a DynamoDB schema for storing and efficiently querying chat message history
  • Explain the connection-tracking problem — knowing which server/connection a given user is currently on
  • Describe how to fan out a message to multiple recipients (group chat) efficiently

Design a Chat Application on AWS is a Pro topic

Sign in, then upgrade to Pro or Power to unlock this topic and the full AWS curriculum.

Related concepts

dynamodb-fundamentalssns-eventbridgelambda-serverless

Next Step

Continue to Design a Video Streaming Platform on AWS