Guided practice

Company tags are community-reported. Counts on cards show how many people reported that design.

• 

  5. Design a Chat System

  Send durable messages, reconnect devices and explain ordering and delivery receipts.

  ClassicMedium

  DatabasesSecurityPrivacy

  +11

  Distributed systemsAWSChatDynamoDBEnd to end encryptionMessagingMulti regionOffline firstOrderingRedis Pub/SubWebSockets

  Worked design

  Practice
• 

  35. WebSocket Gateway and Session Registry

  To push a message to someone you must find the one server out of hundreds that currently holds their connection — and connections are long-lived, unevenly distributed, and disappear without warning.

  Product & backendMedium

  ChatPresenceReal time

  +1

  WebSockets

  Worked design

  Practice

Self-paced by default. Your answers and canvas stay private. AI feedback runs only when you ask for it.