Happy is a revolutionary free, open-source mobile and web client for Claude Code that enables developers to control Claude AI from anywhere with intelligent voice commands, end-to-end encryption, and seamless workflow integration. Born from the frustration of not being able to check on AI coding tools while away from the keyboard, Happy brings the full power of Claude Code to your mobile device.
The project consists of three interconnected components: the Happy mobile app (iOS, Android, Web), Happy CLI for connecting local Claude Code to mobile devices, and Happy Server for secure synchronization. All components are MIT licensed and fully open source, making it accessible to developers worldwide.
Core Features
1. Cross-Platform Mobile Access
Continue the same Claude Code session seamlessly across iOS, Android, and Web platforms. Happy brings the complete Claude Code experience to mobile devices with an interface optimized for touch and voice interaction, allowing you to spawn and control multiple Claude Code instances in parallel from your phone and desktop.
2. Intelligent Voice Commands
Go beyond simple dictation with AI-powered voice commands that understand coding context and execute actions in real-time. The voice interface acts as an intelligent intermediary between you and Claude Code, processing natural language input, maintaining conversational context, and generating structured prompts for immediate execution. Code, debug, and manage projects completely hands-free.
3. End-to-End Encryption
Your code and conversations are protected with military-grade encryption using the same protocol as Signal (TweetNaCl). All messages are encrypted before leaving your device, ensuring complete privacy and security. The Happy Server passes encrypted messages between devices but cannot read your data, maintaining zero-knowledge architecture.
4. Real-Time Synchronization
The Happy Server provides secure synchronization that enables multiple devices to share encrypted conversations while maintaining complete privacy. Work seamlessly across mobile, web, and desktop with instant updates. Support for multiple concurrent Claude Code sessions with independent state management allows sessions to be paused, resumed, and switched between effortlessly.
5. Smart Notifications
Get alerted when your input is needed, when code is ready to review, or when something went wrong. Stay connected to your development workflow even when away from your desk, enabling you to review code, respond to issues, or make quick fixes on the go.
6. Complete Feature Parity
Access all Claude Code features on mobile - from plan mode to custom agents, skills system, and MCP server support. The mobile experience isn't limited; it's the full Claude Code power in your pocket.
Installation & Quick Start
Step 1: Install Happy CLI
npm install -g happy-coder
Step 2: Download the Mobile App
- iPhone/iPad: Download from App Store
- Android: Download from Google Play
- Web App: Access at app.happy.engineering
Step 3: Start Your First Session
happy
This will start a Claude Code session, display a QR code, and enable real-time session sharing between Claude Code and your mobile app.
Step 4: Connect Your Mobile Device Scan the QR code displayed in your terminal to connect instantly.
System Requirements
- Node.js: Version 18 or later (released April 19, 2022)
- Claude CLI: Must be installed and logged in (claude command available in PATH)
- Operating Systems: macOS, Linux, Windows (via WSL)
- Mobile Devices: iOS 14+, Android 8+, or modern web browser
Real-World Use Cases
Mobile Development Workflow One developer shared: "In line at TSA pre-check, I finished another 20% of a magic link app. On the plane, waiting to depart, I deployed it to AWS and made some final DynamoDB schema changes. By the time I returned to NYC, the app was live in Prod."
Code Review on the Go Review pull requests, check on AI assistant progress, and respond to critical issues during coffee breaks, commutes, or while traveling.
Voice-First Coding Use natural language voice commands for hands-free coding sessions, perfect for brainstorming, debugging, or working in environments where typing isn't convenient.
Project Components
| Component | Description | Repository |
|---|---|---|
| Happy | Main mobile and web client application with voice and encryption support | github.com/slopus/happy |
| Happy CLI | Command line tool to connect local Claude Code to mobile devices | github.com/slopus/happy-cli |
| Happy Server | Secure synchronization backend for multi-device support with E2E encryption | github.com/slopus/happy-server |
Privacy & Security
Happy is built with privacy as a core principle:
- Zero Knowledge Architecture: Server cannot read your messages or code
- End-to-End Encryption: Same encryption protocol as Signal (TweetNaCl)
- Local Processing: Claude Code runs on your hardware
- No Vendor Lock-in: Fully open source, MIT licensed
- Transparent Security: All code is auditable on GitHub
Community & Support
Happy is actively maintained by slopus and the open-source community. Community feedback highlights the tool's effectiveness: "Nothing beats github.com/slopus/happy with Claude Code" according to developer reviews.
Get Involved:
- Report issues on GitHub
- Contribute to the open-source project
- Join discussions on Hacker News
- Follow updates at happy.engineering
Comparison with Alternatives
| Feature | Happy | Standard Claude Code | Other Mobile Clients |
|---|---|---|---|
| Mobile Access | ✅ Full support | ❌ Desktop only | ⚠️ Limited |
| Voice Commands | ✅ Intelligent AI | ❌ Not available | ❌ Not available |
| E2E Encryption | ✅ Signal-grade | ⚠️ HTTPS only | ⚠️ Varies |
| Cross-Device Sync | ✅ Real-time | ❌ Not available | ⚠️ Limited |
| Open Source | ✅ MIT License | ⚠️ Proprietary CLI | ⚠️ Varies |
| Cost | ✅ Free | ✅ Free CLI | ⚠️ Often paid |
| Multiple Sessions | ✅ Parallel support | ✅ Yes | ❌ Usually single |
| Offline Capability | ⚠️ Requires connection | ⚠️ Requires API | ⚠️ Varies |
Advantages & Unique Selling Points
Compared to Desktop-Only Solutions:
- True Mobility: Work from anywhere - coffee shops, airports, commutes, or vacations
- Voice-First Interface: Hands-free coding that understands context, not just dictation
- Always Connected: Stay in sync with your projects without being chained to a desk
What Makes Happy Stand Out:
- First truly mobile-optimized Claude Code client with full feature parity
- Military-grade encryption ensuring complete privacy and security
- Intelligent voice commands that go far beyond basic speech-to-text
- Completely free and open source with no vendor lock-in
- Active development and responsive community support
- Parallel session management for complex multi-project workflows
Tips & Best Practices
- Use Voice for Brainstorming: Voice commands excel for high-level planning and architectural discussions before diving into code
- Enable Push Notifications: Stay informed about build status, test results, and when your input is needed
- Set Up Multiple Sessions: Use parallel sessions for different projects or experimental features
- Review Before Committing: Always review code changes on mobile before pushing to production
- Leverage Plan Mode: Use Claude Code's plan mode on mobile for strategic decisions and implementation planning
- Secure Your Device: Since everything is encrypted, your device password is your primary security layer
Frequently Asked Questions
Q: Is Happy secure for sensitive codebases? A: Yes, Happy uses the same encryption protocol as Signal (TweetNaCl) with end-to-end encryption. The server cannot read your messages or code, maintaining zero-knowledge architecture.
Q: Does Happy work offline? A: Happy requires an internet connection to sync with Claude Code and the Happy Server. However, you can review previous conversations offline.
Q: What's the difference between Happy CLI and Happy mobile app? A: Happy CLI runs on your computer and connects local Claude Code to the Happy ecosystem. The mobile app provides the touch and voice interface for controlling Claude Code from your phone.
Q: Can I use Happy with multiple Claude Code accounts? A: Yes, you can manage multiple sessions and switch between them seamlessly on the mobile app.
Q: Is there a cost to use Happy? A: No, Happy is completely free and open source under the MIT license. You only pay for your Claude API usage.
Q: How does Happy handle voice commands? A: Happy's AI-powered voice interface processes natural language, understands coding context, maintains conversational state, and generates structured prompts for Claude Code execution in real-time.
Conclusion
Happy represents a paradigm shift in how developers interact with AI coding assistants, breaking free from desktop constraints to enable truly mobile-first development workflows. With intelligent voice commands, military-grade encryption, and seamless cross-device synchronization, Happy empowers developers to stay productive anywhere.
Whether you're reviewing code during your commute, debugging in a coffee shop, or deploying to production from an airport lounge, Happy brings the full power of Claude Code to your fingertips. Best of all, it's completely free, open source, and built with privacy as a core principle.
Ready to code from anywhere? Install Happy today and experience the future of mobile AI-assisted development.
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