Codex CLI Alternatives

Free and open-source alternatives to Codex CLI

• Aideropen source
• Gemini CLIopen source
• Opencodeopen source
• Crushfree
• Qwen Codeopen source
• Spec Kitopen source
• Gooseopen source

Codex CLI alternatives in detail

1. Aider

   open sourceCLI

   Aider is an open-source (Apache-2.0) command-line tool for AI pair programming. Run it inside a Git repository, describe a change in plain language, and it edits files on disk and commits each step with a descriptive message. Model-agnostic: bring your own API key for Claude, GPT, and others; a repo map gives the model context in large codebases.

   Read: AI Coding Agents in 2026: The Open-Source & CLI Edition

   Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

2. Claude Code

   paidCLI

   Claude Code is Anthropic's official agentic coding tool for the terminal, IDE (VS Code, JetBrains), and web. It works as an agent rather than autocomplete: it reads your codebase, plans changes, edits files, runs commands, and iterates against test or build feedback. Extensible via MCP servers, slash commands, subagents, and hooks; requires a paid plan.

   Read: Claude Code vs Codex CLI: Terminal Agents Compared (2026)

   Read: Claude vs GPT vs Gemini for Coding in 2026

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3. Gemini CLI

   open sourceCLI

   Gemini CLI is Google's open-source (Apache-2.0) terminal AI agent for Gemini models, with a 1M-token context window, file and shell tools, Google Search grounding, MCP, and GEMINI.md files. Since June 18, 2026 it no longer serves free or Google AI Pro/Ultra users, who are pointed to Antigravity CLI; paid API keys and enterprise Code Assist still work.

   Read: Claude vs GPT vs Gemini for Coding in 2026

   Read: AI Coding Agents in 2026: The Open-Source & CLI Edition

   Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

4. Opencode

   open sourceMITmacOS, Windows, LinuxCLI

   OpenCode is the most-starred open-source coding agent (~206k GitHub stars by September 2026) — a terminal TUI from Anomaly (formerly SST) that works with 75+ model providers including local ones, loads language servers for code intelligence, runs parallel sessions, and shares them via links. MIT-licensed; bring your own keys or use the optional Zen gateway.

   Read: AI Coding Agents in 2026: The Open-Source & CLI Edition

   Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

5. Crush

   freeFSL-1.1-MITmacOS, Windows, Linux, AndroidCLI

   Crush is Charm's free terminal coding agent. It continues opencode-ai/opencode (archived; last push September 2025), not today's OpenCode. It runs nearly any model, including local ones, switches models mid-session and adds LSP context, MCP and Agent Skills. It is source-available under FSL-1.1-MIT, not OSI open source; releases turn MIT after two years.

   Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

6. Qwen Code

   open sourceApache-2.0macOS, Windows, LinuxCLI

   Qwen Code is the Qwen team's free, Apache-2.0 coding agent, originally forked from Gemini CLI. It speaks OpenAI, Anthropic, Gemini and Qwen APIs, runs local models via Ollama or vLLM, and ships subagents, hooks, MCP and plan mode. The free Qwen OAuth quota ended April 15, 2026, so bring an API key, an Alibaba Cloud plan or a local model.

   Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

7. Spec Kit

   open sourceMITmacOS, Windows, LinuxCLI

   Spec Kit (GitHub, MIT, ~111k stars since its September 2025 launch) productized spec-driven development: specify init scaffolds a project, then /speckit.constitution, .specify, .plan, .tasks, and .implement walk your coding agent through the pipeline — each phase emitting a markdown artifact that feeds the next. Works with 30+ agents including Claude Code, Copilot, and Cursor.

8. Amp

   freemiumAgent

   Amp is an agentic coding tool that spun out of Sourcegraph in December 2025: a CLI plus apps for the web, Mac, iPhone, and iPad that run frontier models to read, edit, and run commands across a repository. Subagents parallelize independent sub-tasks, the Oracle adds a second-opinion reasoning model, and threads can be shared with a workspace.

   Read: The Best GitHub Copilot Alternatives in 2026 (Free and Paid)

   Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

9. Factory

   paidAgent

   Factory is an agent-native software development platform. Its autonomous coding agents, called Droids, plan, write, test, and ship code across the terminal (Droid CLI), IDE, and web, pulling in organizational context from GitHub, Jira, Slack, and your codebase. It targets individual developers and enterprise engineering teams.

   Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

10. Goose

    open sourceAgent

    Goose is an open-source (Apache-2.0), general-purpose AI agent that runs entirely on your machine — it executes shell commands, edits files, runs tests, and chains multi-step tasks. MCP-native with 70+ documented extensions and model-agnostic across 15+ providers including local models, it ships as a Rust CLI and a desktop app for macOS, Linux, and Windows.

    Read: AI Coding Agents in 2026: The Open-Source & CLI Edition

    Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

11. Jules

    freemiumWebAgent

    Jules is Google Labs' asynchronous coding agent, free for up to 15 tasks a day. You connect a GitHub repo and describe a task; Jules works in a Google-hosted VM, proposes a Gemini-built plan, shows diffs for approval and opens a pull request. It is proprietary and labeled experimental, and its changelog's latest entry is March 9, 2026.

    Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)

12. Kiro

    freemiummacOS, Windows, Linux, WebIDE

    Kiro is AWS's spec-driven coding agent for the IDE, terminal and web, with a free plan. It turns a prompt into requirements, a design and sequenced tasks, then checks the code against them with property-based tests. It is proprietary, and one agent harness carries specs, hooks and MCP servers across the IDE, the kiro-cli agent and Kiro Web.

    Read: The Best GitHub Copilot Alternatives in 2026 (Free and Paid)

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13. Warp

    freemiumTerminal

    Warp is an AI-powered terminal whose agent can plan, run, and chain commands while you approve what executes. Output is grouped into navigable blocks, workflows share vetted commands, and the agent grounds itself in your indexed codebase. A standalone Warp Agent CLI followed in August 2026. The client is open source (mostly AGPL-3.0), with a free tier.

    Read: The Best Claude Code Alternatives in 2026 (Free, Open-Source, and Paid)