8 Best Happy Alternatives in 2026 (Open Source)

Happy — Mobile and Web client for Codex and Claude Code, with realtime voice, encryption and fully featured. Only mobile client for Claude Code and Codex with E2E encryption and instant device switching — vs being tethered to your desktop while agents run

These 8 open-source tools do the same job. They are ordered by how closely they match Happy, with live GitHub data so you can see which projects are actively maintained.

1. 1. Claude Code

   Claude Code is an agentic coding tool that lives in your terminal, understands your codebase, and helps you code faster by executing routine tasks, explaining complex code, and handling git workflows

   What sets it apart: Unlike Codex (OpenAI) which also runs in terminal, Claude Code has deeper codebase understanding via long-context and native GitHub integration with @claude mentions

   Best for: Developers who live in the terminal and want AI-assisted coding without leaving CLI; Teams using GitHub workflows who want automated PR reviews and code generation

   ⭐ 148.7kHappy vs Claude Code →Full profile →

2. 2. Codex

   Lightweight coding agent that runs in your terminal

   What sets it apart: Unlike Claude Code (Anthropic-only), Codex uniquely integrates with existing ChatGPT subscriptions and offers both CLI and cloud-based (Codex Web) agent variants

   Best for: OpenAI ecosystem users wanting a terminal-first coding agent with ChatGPT plan integration; Teams already paying for ChatGPT Enterprise who want CLI-based code automation

   ⭐ 127.4kHappy vs Codex →Full profile →

3. 3. GPT Mobile

   Chat app for Android that supports answers from multiple LLMs at once. Bring your own API key AI client. Supports OpenAI, Anthropic, Google, and Ollama. Designed with Material3 & Compose.

   What sets it apart: vs ChatGPT/Claude apps: Open-source Android-native app that lets you chat with multiple LLMs simultaneously in one conversation, with Material You design and fully local chat storage

   Best for: Android users wanting to compare multiple LLM responses side-by-side; Privacy-conscious users who want local-only chat history

   ⭐ 1.2kHappy vs GPT Mobile →Full profile →

4. 4. Chatbox

   Powerful AI Client

   What sets it apart: vs ChatGPT web app: supports multiple LLM providers with local data storage; vs Open WebUI: lighter desktop-native app with mobile support rather than self-hosted web UI

   Best for: Desktop users wanting unified LLM chat interface; Privacy-conscious users preferring local data storage; Teams sharing API resources

   ⭐ 41.9kHappy vs Chatbox →Full profile →

5. 5. NextChat

   ✨ Light and Fast AI Assistant. Support: Web | iOS | MacOS | Android | Linux | Windows

   Best for: Privacy-conscious users wanting local-only AI chat with multi-provider support; Teams needing a quick-deploy ChatGPT alternative on their own infrastructure; Organizations seeking a brandable, customizable AI chat interface

   ⭐ 88.8kHappy vs NextChat →Full profile →

6. 6. Cherry Studio

   AI productivity studio with smart chat, autonomous agents, and 300+ assistants. Unified access to frontier LLMs

   What sets it apart: Unlike Lobe Chat (web-first) or AnythingLLM (RAG-focused), Cherry Studio is a polished Electron desktop client purpose-built for multi-provider LLM access with 300+ pre-built assistants and MCP support, requiring zero environment setup.

   Best for: Power users who want a single desktop app to access multiple LLM providers without switching between web UIs; Users who need side-by-side multi-model comparison for prompt testing; Non-technical users wanting a ready-to-use ChatGPT-like desktop experience with no environment setup

   ⭐ 52.3kHappy vs Cherry Studio →Full profile →

7. 7. Gemini CLI

   An open-source AI agent that brings the power of Gemini directly into your terminal.

   What sets it apart: Unlike Claude Code ($20+/month) and Codex (ChatGPT subscription), Gemini CLI offers the most generous free tier (1,000 req/day) with 1M token context and built-in Google Search grounding

   Best for: Developers wanting a free, high-quota AI coding CLI with 1M token context for large codebases; CI/CD pipelines needing automated AI-powered PR reviews via GitHub Actions

   ⭐ 107.2kHappy vs Gemini CLI →Full profile →

8. 8. GPT-Code

   An open source implementation of OpenAI's ChatGPT Code interpreter

   What sets it apart: vs ChatGPT Code Interpreter / Open Interpreter: self-hosted open-source web UI for AI code generation and execution — own your data and conversations without ChatGPT Plus subscription

   Best for: Self-hosted Code Interpreter alternative; Data analysis and visualization with AI assistance; Document processing and automation scripting

   ⭐ 3.5kHappy vs GPT-Code →Full profile →