# WhatsApp System Design

Quick Reference: Step 7: Message Queues | Step 10: Encryption

# Quick Reference

Scale: 2B+ users, 100B+ messages/day

Key Components: Messaging, real-time delivery, end-to-end encryption, presence

Challenges: Real-time delivery, encryption, presence updates

# Clear Definition

WhatsApp is a messaging platform requiring real-time message delivery, end-to-end encryption, and presence management at massive scale.

💡 Key Insight: WhatsApp uses Erlang for concurrency, message queues for delivery, and end-to-end encryption for security.

# Core Concepts

# Architecture

• Message Queue: Handle message routing
• Presence: Track online/offline status
• Encryption: End-to-end encryption
• Media: Store and deliver media files

# Quick Reference Summary

WhatsApp: Messaging platform with encryption and real-time delivery.

Key Components: Message queues, presence, encryption.

Key Design: Erlang for concurrency, message queues, end-to-end encryption.

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