Which AI tool? · updated
Which free, open-source AI coding agent should you use?
OpenAI Codex is our top pick for a free, open-source coding agent, out of 7 tools we compared. Coding agent available in the CLI, IDE and cloud; good for parallel background tasks.
Quick picks
- Top pick: OpenAI Codex. Coding agent available in the CLI, IDE and cloud; good for parallel background tasks.
- Free plan or tier in our sourced pricing facts: OpenAI Codex, OpenCode, Mirror CLI, Croo and fx.
- Open source: OpenAI Codex, OpenCode, Aider, Mirror CLI, Garuda, Croo and fx.
The 7 tools, in order
From official sites- #1 OpenAI Codex
- Coding agent available in the CLI, IDE and cloud; good for parallel background tasks.Pricing: Included in ChatGPT Free ($0), Go ($8 a month), Plus ($20 a month), Pro (from $100 a month, with $100, $200 and $500 tiers), Business, Edu and Enterprise plans. Source: developers.openai.com, checked Official site: openai.com · Our profile
- #2 OpenCode
- Open-source coding agent with terminal, desktop and web clients on one shared local service; bring any model.Pricing: OpenCode itself is 100% free and open source. Source: opencode.ai, checked Official site: opencode.ai · Our profile
- #3 Aider
- Open-source, git-native pair programmer that works with many models.License: Open source, Apache License 2.0. Source: github.com, checked Official site: aider.chat · Our profile
- #4 Mirror CLI
- Reflection's open-source (Apache-2.0) terminal coding agent, in early beta. Runs parallel tasks in separate worktrees and defaults to Reflection's open-weight Beam model, with OpenAI, Anthropic and OpenRouter as options.Pricing: The CLI is free and open source. Source: github.com, checked Official site: github.com · Our profile
- #5 Garuda
- Free, open-source (Apache-2.0) terminal agent that runs commands in an OS sandbox and asks before edits; works with Claude, OpenRouter or local models.License: Open source, Apache License 2.0. Source: github.com, checked Official site: madhu-sv.github.io · Our profile
- #6 Croo
- Small, free, MIT-licensed coding agent that is now a Mac app as well as a terminal tool. Sign in with your Claude or ChatGPT plan, paste an API key, or run a local model, and every edit and command waits for your OK. Apple Silicon only for the app, and still young.Pricing: Free and open source (MIT). Source: ai.crooli.com, checked Official site: ai.crooli.com · Our profile
- #7 fx
- Vercel Labs' open-source (Apache-2.0) terminal agent shipped as one small native binary for macOS and Linux. Bring a ChatGPT or Grok subscription, Vercel AI Gateway, or any OpenAI-compatible endpoint such as Ollama. Experimental and pre-1.0, so use with care.Pricing: Free and open source. Source: github.com, checked Official site: fx.sh · Our profile
Method
How we ordered this list
This list is the open-source tools from our coding agents ranking, in the same order as that ranking. Claude Code is our number one overall there, but it is not listed here because its official pricing page says it is included with paid Claude plans and not the Free plan. Open source does not always mean free to run, since most of these agents bill you for the AI model you connect. Gemini CLI is open source but was removed from this list on November 10, 2026, because it no longer has a free tier for individuals. How we rank
What changed
Gemini CLI is now for business licenses only: what free users can switch to
Next steps
Related comparisons
All comparisonsQuestions
Frequently asked
Which free, open-source AI coding agent should you use?
OpenAI Codex is our top pick for a free, open-source coding agent. Coding agent available in the CLI, IDE and cloud; good for parallel background tasks. The other 6 we compared: OpenCode, Aider, Mirror CLI, Garuda, Croo and fx.
Which of these tools have a free plan?
Free plan or free tier in our sourced fact sheets: OpenAI Codex, OpenCode, Mirror CLI, Croo and fx (5 of 7). Prices change, so confirm on the official pricing page before you buy.
Which of these tools are open source?
Open source per their official pages: OpenAI Codex, OpenCode, Aider, Mirror CLI, Garuda, Croo and fx.
How is this list ordered?
This list is the open-source tools from our coding agents ranking, in the same order as that ranking. Claude Code is our number one overall there, but it is not listed here because its official pricing page says it is included with paid Claude plans and not the Free plan. Open source does not always mean free to run, since most of these agents bill you for the AI model you connect. Gemini CLI is open source but was removed from this list on November 10, 2026, because it no longer has a free tier for individuals.
Are any placements sponsored?
Some placements on AI Tool Podium are sponsored. Every sponsored placement is clearly labeled.
When was this page last updated?
This page was last updated on 2026-11-13. Features and prices change often, so check each official site before you buy.
Sources
- OpenAI Codex official site: openai.com/codex
- OpenAI Codex pricing source: developers.openai.com/codex/pricing
- OpenCode official site: opencode.ai
- OpenCode pricing source: opencode.ai/console/go
- Aider official site: aider.chat
- Mirror CLI official site: github.com/reflection-oss/mirror
- Mirror CLI pricing source: github.com/reflection-oss/mirror/blob/main/mirror-cli/README.md
- Garuda official site: madhu-sv.github.io/garuda
- Croo official site: ai.crooli.com
- Croo pricing source: ai.crooli.com
- fx official site: fx.sh
- fx pricing source: github.com/vercel-labs/fx
More answers