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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-commits to 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 filename so Aider knows which files to modify
  • Use the /undo command 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