Best Free & Open Source Alternatives to Claude Code

Pi is an open-source AI agent toolkit built by Earendil Works. It includes an interactive coding agent CLI that helps you write, refactor, and debug code in real time—similar to Claude Code and OpenAI Codex. The project also provides a unified multi-provider LLM API supporting OpenAI, Anthropic, Google, and others, plus a terminal UI library with differential rendering for building rich CLI experiences.

The monorepo is organized into focused packages: the coding agent CLI, an agent runtime with tool calling and state management, the unified LLM API layer, and a TUI library. Pi is designed to be self-extensible and treats security seriously, with supply-chain hardening measures like pinned dependencies, shrinkwrap generation, and npm audit integration.

OpenCode is a terminal-based AI coding agent that assists developers with code generation, editing, and problem-solving directly from the command line, IDE, or desktop. It connects to over 75 LLM providers — including Claude, GPT, Gemini, and local models — and allows multiple parallel agent sessions to run simultaneously on the same project.

Key features include automatic language server protocol (LSP) loading for the relevant codebase context, shareable session links for collaboration and debugging, and support for GitHub Copilot and ChatGPT account integrations. No code or context data is stored by the platform, keeping sensitive codebases private.

OpenCode is built for developers who want an AI coding assistant that is flexible about model choice, works in their existing terminal or editor workflow, and does not tie them to a single proprietary AI provider or impose restrictions on how their code is handled.

MiMoCode is a terminal-native AI coding assistant built as a fork of OpenCode. It can read and write code, run commands, manage Git, and use a persistent memory system to keep a deep understanding of your project across sessions while continuously improving itself.

Key features include multiple agents (build, plan, compose), a persistent cross-session memory system powered by SQLite FTS5, intelligent context management with automatic checkpoints and context reconstruction, a tree-shaped task tracking system, a subagent system for parallel work, goal/stop condition evaluation via a judge model, compose mode for specs-driven development, real-time voice input, and self-improvement via dream and distill commands.

MiMo Auto is built in as a free-for-limited-time channel for zero-configuration start. MiMoCode also supports connecting to any mainstream LLM provider via OpenAI-compatible APIs, including custom providers. It is an open-source alternative to proprietary AI coding assistants like Claude Code, GitHub Copilot, Cursor, Windsurf, and Codeium.

Juggler is a self-hostable AI coding agent built around a visual workbench rather than a chat transcript. Where most coding agents give you a single linear doom-scroll, Juggler stores the session as an editable Yjs document you can branch, inspect, and rewind — tool calls, thread structure, item properties, and raw context laid out in Finder-style Miller columns instead of buried in collapsible chat.

Everything important is a JavaScript extension. The LLM tools (read-file, replace-text, bash, etc.), slash commands, and even the high-level orchestration strategies like plan or research are plugins you can inspect, fork, or replace. The extension SDK and bundled extensions ship under Apache-2.0, so writing your own — including closed-source ones — carries no copyleft obligation.

The desktop app is a native client built with Go and Wails (no Electron). Underneath, Juggler is a local webserver serving a live collaborative session that any number of clients — the desktop app, a browser tab, a phone — can attach to. The server is localhost-only by default and exposes a headless mode for long-lived, remote, or network-accessible sessions; commercial WAN-access features live in the official juggler.studio binaries and are not part of this repository. Juggler supports the usual model providers, including Claude Code, OpenAI (codex plan or API), Gemini, Ollama, OpenRouter, Z.AI, and Deepseek. Compared to Cursor, GitHub Copilot, Windsurf, or Codex, it trades polish and ecosystem for full visibility and control over the loop.