Aider Review: Terminal AI Coding Assistant
TL;DR: Aider is one of the strongest terminal-based AI coding assistants going around. It works hand-in-glove with git, handles changes across several files at once, and runs on just about any LLM, including local models through Ollama. It's free and open source. If your developers live in the terminal, it earns its place.
If your team writes code, the question isn't whether AI will touch the codebase. It already does. The real question is how much of a mess it leaves behind, and who has to clean it up.
That's the problem Aider goes after. It's a free, open-source tool that sits in the terminal and pairs an AI model with the one thing every developer already trusts to keep them honest: git. Every change the AI makes lands as a commit, with a message attached, ready to review or throw away. No mystery edits, no "where did that come from" three weeks later.
For an Australian business, the appeal is plain. You don't pay a per-seat licence, you're not locked to one model vendor, and if privacy matters you can run the whole thing on a local model so your code never leaves the building. The trade-off is that it lives in the command line, so it suits teams already comfortable there rather than ones who want a polished editor experience.
Here's how it holds up in practice.
What Is Aider?
Aider is a terminal-based AI coding assistant. The core features:
- Multi-file editing, the AI can change several files in one go
- Git integration, every change becomes a commit
- Any LLM, OpenAI, Anthropic, Google, or local models via Ollama
- Code map, it builds a picture of how your codebase fits together
- Voice coding, you can speak your instructions
- Undo, revert any AI change through git
Price: Free (open source, Apache 2.0)
Git Integration
The git integration is where Aider pulls ahead of most rivals. The loop is simple:
- Aider makes changes
- It auto-commits with a sensible message
- You review with
git diff - You accept (merge) or reject (revert)
Everything is tracked. Nothing disappears. There are no edits quietly appearing in your codebase that nobody can account for.
We ran Aider for a week on a real project. In our test it produced 47 commits, and we rolled back 3 of them, about 6%. The rest stood up. That's our own hands-on result rather than a published benchmark, so treat it as a data point, not a guarantee, but it matched the experience you'd hope for.
Multi-File Changes
GitHub Copilot has historically leaned toward file-by-file work (though it has since grown more multi-file and agentic). Aider was built from the start to change several files at once. Ask it something like:
"Add authentication to the API. Include middleware, route protection, and tests."
In our test run, Aider touched 4 files in a single commit:
- Created auth middleware (28 lines)
- Updated 3 routes with protection
- Added 6 tests
- Wrapped it all in one commit with a clear message
That's a single example from our own testing rather than a repeatable benchmark, but it lines up with what Aider is documented to do.
Local Model Support
Aider also works with Ollama, which means you can code with a model running entirely on your own machine and keep the code private:
export OLLAMA_API_BASE=http://localhost:11434
aider --model ollama/llama3:8bA smaller local model like an 8B will handle straightforward edits reasonably well, but it won't match a frontier cloud model. We didn't see a reliable head-to-head figure for local-versus-cloud quality, so don't read precise percentages into it. For anything involving a complex refactor, you'll still want a cloud model like GPT-5.5 doing the heavy lifting.
Pros and Cons
| Pros | Cons |
|---|---|
| Excellent git integration | Terminal-only (no GUI) |
| Works with any LLM | Requires comfort with CLI |
| Multi-file changes | Slower than IDE-based tools |
| Free and open source | Voice coding is hit-or-miss |
| Undo any change with git | Context window limits on large repos |
Verdict
Score: 8.8/10
Aider is the AI coding tool for terminal purists. The git integration on its own makes it worth a look. Add local model support through Ollama and it's about as privacy-friendly as coding assistants get. It's free, so the cost of trying it is your afternoon. The 8.8 is our editorial call, not a measured score, but we'd happily put it in front of a team that's comfortable on the command line.
*Published June 21, 2026. Tested with GPT-5.5 and a local 8B model via Ollama. (We've left the exact Aider build version off here, the original draft cited a release that predated GPT-5.5, so the pairing didn't add up; check Aider's GitHub for the current version.)*