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chat-system

Design scalable real-time chat systems with WebSocket gateways and offline delivery.

Updated Jun 5, 2026
Search Tags:#WebSocket#real-time chat#end-to-end encryption#chat system design#WhatsApp scale#presence synchronization#offline message delivery
One-click install
npx skills add https://github.com/hung-phan/system-skills --skill chat-system-hung-phan
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: chat-system
Source: https://github.com/hung-phan/system-skills/tree/main/skills/system-review/references/interview-templates/chat-system
Command: npx skills add https://github.com/hung-phan/system-skills --skill chat-system-hung-phan

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes scripts (resource) and references (resource) components.

What problem does it solve?

This Skill empowers you to design and understand real-time chat systems at the scale of WhatsApp/Slack/Messenger, handling complex challenges like concurrency, presence, and offline delivery.

Core Features & Use Cases

  • Real-time Chat Design: Offers comprehensive guidelines for designing scalable chat systems with features like WebSocket gateways, presence handling, message ordering, and offline delivery.
  • Use Case: Design a robust chat system capable of handling high traffic and complex scenarios such as multiple concurrent connections, mobile offline behavior, and end-to-end encryption.
  • Offline Message Handling: Ensures seamless message delivery even when users are offline or the network is unreliable.

Quick Start

Design a real-time chat system with support for end-to-end encryption and offline delivery using the chat-system skill.

Frequently Asked Questions about chat-system

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I design a real-time chat system that handles WhatsApp-scale concurrency?▼

Designing a real-time chat system for WhatsApp-scale concurrency requires WebSocket gateway architectures for connection management and distributed systems to handle massive simultaneous traffic. This provides comprehensive guidelines for presence synchronization and message sequencing.

What is the best way to handle offline message delivery in a chat application?▼

Offline message delivery in a chat application ensures seamless message delivery when users are offline or on unreliable networks. It requires mechanisms to queue messages and synchronize them once connectivity resumes.

How does presence synchronization work in large-scale messaging platforms?▼

Presence synchronization in large-scale messaging platforms tracks user online status across distributed nodes. It relies on network protocols and WebSocket connections to broadcast state changes efficiently to concurrent connections.

Can I implement end-to-end encryption in a WebSocket-based chat system?▼

End-to-end encryption can be implemented in a WebSocket-based chat system by applying encryption protocols directly within the message sequencing strategies. This ensures secure communication across large-scale distributed systems.

What message sequencing strategies are needed for high-traffic real-time chat?▼

Message sequencing strategies for high-traffic real-time chat ensure correct message ordering during concurrent connections. They leverage distributed systems design to maintain consistency across WebSocket gateways and offline message delivery.

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