Aider
Aider is an open-source AI pair programming tool that runs in your terminal. It connects to many different LLMs and integrates directly with git, automatically committing changes as it works.
Installation
pip install aider-chat
Or using uv (recommended for faster installs):
uv tool install aider-chat
Or via pipx:
pipx install aider-chat
Starting Aider
Change into your project directory and run:
aider
This starts an interactive pair programming session. You can also specify a model and files to work with upfront:
aider --model sonnet src/app.py src/models/user.py
For a single non-interactive message, use the -m flag:
aider -m "add input validation to the signup handler"
Authentication
Aider does not bundle its own AI model. You provide API keys for the model you want to use:
export ANTHROPIC_API_KEY=sk-... # for Claude
export OPENAI_API_KEY=sk-... # for GPT models
export DEEPSEEK_API_KEY=sk-... # for DeepSeek
For local models, connect via Ollama or any OpenAI-compatible API endpoint.
Key features
Git-native workflow
Aider automatically creates git commits for every change it makes, with descriptive commit messages. This gives you a clean history and makes it easy to review or revert any AI-generated change.
aider --auto-commits
Model-agnostic
Aider supports 100+ LLMs including Claude, GPT-4, DeepSeek, Gemini, Llama, and many others. Switch models on the fly:
aider --model claude-sonnet-4-20250514
aider --model gpt-4o
aider --model deepseek/deepseek-coder
aider --model ollama/llama3 # local model
Codebase mapping
Aider builds a map of your entire repository using tree-sitter, understanding function signatures, class hierarchies, and file relationships. This helps it make targeted changes without needing to read every file into context.
Voice-to-code
Aider supports voice input, letting you describe changes by speaking rather than typing. Useful for hands-free coding or when you want to explain a change conversationally.
Watch mode
Run Aider in watch mode to monitor files for special comments. Add a # ai: <instruction> comment in your code, and Aider picks it up and acts on it:
aider --watch-files
Tips
- Use
--auto-commitsto keep a clean git history of all AI changes - Start with Claude or GPT-4 for best results; switch to DeepSeek or local models for cost savings
- Add files explicitly to the chat with
/add filenameso Aider knows which files to modify - Use the
/undocommand to revert the last AI change if it's not what you wanted
Limitations
- CLI-only: no GUI or IDE integration (though it works alongside any editor)
- Requires you to supply your own API keys and manage model costs separately
- Quality depends heavily on the underlying model you choose