Aider is a free, open-source AI coding tool that runs in your terminal. You describe what you want in plain English, and it edits your code files directly. Every change is automatically saved as a Git commit.
What makes Aider different
Unlike Claude Code (Claude only) or Codex CLI (GPT only), Aider works with ANY AI model — Claude, GPT, Gemini, DeepSeek, Qwen, or local models via Ollama.
Key features
- Any model — 100+ models supported, including free local ones
- Git-native — every AI edit is a clean Git commit
- Multi-file editing — coordinates changes across your entire project
- Auto-lint and auto-test — fixes linting errors and failing tests automatically
- Voice input — describe changes by speaking
- Repository map — builds a map of your codebase for better context
- Architect mode — uses a strong model to plan, then a fast model to implement
How it works
When you start Aider in a project, it builds a “repository map” — a condensed representation of your codebase showing file structure, function signatures, and class hierarchies. This map helps the AI understand your project without sending every file.
You then describe what you want changed. Aider sends your request plus relevant context to the AI model, receives back a structured diff, and applies it to your files. If the change introduces linting errors or test failures, Aider automatically attempts to fix them.
Every successful change is committed to Git with a descriptive message, giving you a clean history of AI-assisted changes that you can review, revert, or cherry-pick.
Quick start
pip install aider-chat
cd your-project
aider --model deepseek/deepseek-chat # or any modelArchitect mode
Aider’s architect mode uses two models: a powerful “architect” model plans the changes, then a fast “editor” model implements them. This gives you the reasoning quality of Claude Opus with the speed and cost of a smaller model.
aider --architect --model claude-opus --editor-model deepseek/deepseek-chatWho is Aider for?
- Developers who want AI coding without vendor lock-in
- Teams on a budget (use cheap models like DeepSeek for $3/month)
- Privacy-conscious developers (use local models)
- Anyone who wants transparent Git history of AI changes
Aider vs Claude Code vs OpenCode
| Aider | Claude Code | OpenCode | |
|---|---|---|---|
| Models | Any (100+) | Claude only | Any |
| Git commits | ✅ Auto | Manual | Manual |
| LSP | ❌ No | Partial | ✅ Deep |
| Architect mode | ✅ Yes | ❌ No | ❌ No |
| Price | Free (BYOK) | $20/mo sub | Free (BYOK) |
FAQ
How much does it cost to use Aider daily?
Aider itself is free. Your cost depends on the model you choose. With DeepSeek Chat at $0.27/$1.10 per million tokens, most developers spend $3-10/month. With local models via Ollama, the cost is $0 beyond electricity.
Can Aider handle large refactoring tasks across many files?
Yes. Aider’s repository map and multi-file editing capabilities let it coordinate changes across dozens of files. For very large tasks, architect mode is recommended — it uses a powerful model to plan the full refactoring strategy, then a fast model to implement each change systematically.
What’s the best model to use with Aider?
For the best quality, Claude Sonnet 4.6 or Claude Opus 4.6 are top choices. For the best value, DeepSeek Chat delivers ~85% of Claude’s quality at 1/50th the cost. For free local use, Devstral Small 24B or Qwen 3.5 27B via Ollama work well.
Learn more
- Aider Complete Guide — full setup, commands, and configuration
- Aider vs Claude Code vs Codex CLI — detailed comparison
- How to Use Aider with DeepSeek — the $3/month setup