What is Aider?
Aider is an open source coding agent that lives in the terminal and treats Git as part of the workflow: every change the AI makes lands as a reviewable commit with its own message, so undoing or reviewing is trivial. It works with more than 75 model providers, including local models via Ollama, and it is free: you only pay for the tokens of whichever model you choose.
Pros
- Free and open source, no subscription
- Every AI edit is a reviewable Git commit
- Works with more than 75 providers, including local models
- Architect mode: a strong model plans and a cheap one edits
Cons
- You have to bring your own API key and pay for tokens
- No graphical interface: everything happens in the terminal
- Needs more setup than a commercial tool
Frequently asked questions
Is Aider free?
Yes, the program is free and open source under the Apache 2.0 licence. You only pay for the API usage of whichever model you connect, or nothing at all if you use local models with Ollama.
Which models does it support?
More than 75 providers: Claude, GPT, Gemini and local models through Ollama, among others.
What is architect mode?
It sends your request to a strong model that proposes how to solve it, then passes that proposal to a cheaper model that turns it into concrete edits. You get good reasoning at lower cost.