Happy Coder (abbreviated as Happy) is an open-source multi-model orchestration client, positioned as a unified entry point for Claude, Codex, and Grok, and covering both mobile and web. It is driven by "Happy Harness," which the official description calls "any model, your subscription, Happy Harness."
In terms of purpose, Happy is used to orchestrate Claude, Codex, and Grok within a single app. The official description states that each model retains its vendor's own prompts and tools, users can choose the more suitable model for each task, and delegate tasks to subagents on any model.
Main capabilities include: 1. A unified entry point for multiple providers, centralizing Claude, Codex, and Grok in one app while retaining each vendor's own prompts and tools; 2. Reusing existing subscriptions, users can log in directly with their already-paid Claude, Codex, and Grok subscriptions, and Happy only adds a harness layer without generating new bills; 3. Open source (MIT license), running on the user's own hardware, with the project remaining an ordinary folder, allowing users to read the code, fork it, and publish their own builds; 4. An end-to-end encrypted mobile app, where the same session appears on the phone after leaving the computer, and content transmitted between devices is encrypted; 5. Native multiplayer collaboration, allowing deployment of a team server to work together, with each person logging in as themselves and sharing the same projects and sessions.
In terms of usage, the official emphasis is "if you like the terminal, keep the terminal." Users can start Claude Code or Codex in the terminal, then resume that session or create a new session from their phone, without needing a desktop app. The official website provides a Download Happy entry point and gives an overall description: start Claude Code or Codex in the terminal, and you can resume the session or start a new session on your phone. Details such as installation commands and specific download addresses are not yet provided.
Applicable scenarios include: developers who want to use multiple models simultaneously in one interface; users who already subscribe to Claude, Codex, or Grok and want to reuse their existing subscriptions without paying extra; people who need to continue a session on their phone after leaving their workstation; teams that want to self-deploy, audit the code, and ensure data stays on their own hardware; and collaborative teams that need multiple people to share projects and sessions.
Limitations and information not provided: the official page mentions rating data (4.9 points, 1000+ ratings; 5.0 points, 3.1k+ reviews), but does not give specificpricing plans (only stating free and open source), system requirements for each platform, supported terminal types, installation commands, the specific implementation of voice features, and details of team server deployment. This information is not yet provided in this material.
