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Aider

Free terminal coding agent, with Git built in.

4.4FreeCoding

Price: Free and open source (Apache 2.0). You only pay for the API of the model you use, or nothing if you run it locally with Ollama.
Platforms: Windows · Mac · Linux
Free plan: yes
API available: no
Open source: yes
Available in Spanish: yes

We review pricing and features regularly, but check them on the official site before subscribing. How we review.

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

What Aider is like in practice

Where it stands out

It is open source, works with whichever API you connect and uses Git explicitly: one commit per change, so reverting when it gets things wrong is trivial. That combination — choosing the model, paying only for what you use and having history as a safety net — no commercial alternative offers.

Where it falls short

It lives in the terminal and assumes a fair amount of Git: if you are not comfortable with branches and reverts, its working model will not sit well. It does not autocomplete as you type and has no visual interface for reviewing changes before applying them, which is what gives newcomers to agents confidence.

How its pricing works

The software is free and you only pay for the API of whichever model you connect: a few small fixes cost cents while a multi-file refactor can run to several euros in one session. You can use a cheap model for mechanical work and an expensive one for the hard parts, which is where the savings are.

Is Aider right for you?

Yes, if…

You work in a terminal, want minimal cost and care about history: each AI edit lands as a reviewable Git commit. It works with 75 providers, including local models.

No, if…

You prefer a graphical interface or want everything working without setup: you have to bring an API key and configure it. Cursor or Claude Code come ready out of the box for that.

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.

Compare Aider head to head

Pricing, features and limits of Aider against its direct rivals.

Where Aider appears

Rankings where we have picked this tool.

Alternatives to Aider