Good for / not for
- Developers who live in a terminal and want AI edits that show up as normal git commits.
- Anyone who wants to pick their own model — OpenAI, Anthropic, DeepSeek or a local one through Ollama.
- Learning how an AI coding agent works, because every step it takes is visible in the chat and in git log.
- Small, focused changes across a few files where you name the files yourself.
- People who want a graphical editor with a chat panel — there is no GUI.
- Teams that need MCP servers or tool integrations; Aider does not support MCP.
- Anyone who wants a product that ships a new version every week — releases have stalled.
What it actually does
You start Aider inside a git repository and add the files you want it to work on with /add. Then you type what you want in plain English — add a flag, fix a bug, write a test — and Aider sends the relevant files and your request to the model you configured. It reads the reply, applies the edits directly to your files and makes a git commit with a message describing the change. That commit is the whole point: you review it with git diff, keep it, or type /undo and it is gone. Nothing lands in your codebase without a commit you can inspect. Aider works with any model that its LiteLLM layer can reach, which covers the major API providers and local models served by Ollama, so switching models is a flag, not a migration. It also builds a lightweight map of your repository so the model knows what functions exist beyond the files you added. There is no editor plugin to install and no account to create; the tool is a Python package and your API key.
aider cli.py, then: "add a --verbose flag that prints each step"
Aider proposes a diff to cli.py, applies it, and commits it with a generated message. git log shows the change as its own commit; /undo reverts it.
From the vendor's docsPricing and free-plan limits
Free tier: Everything is free; you pay your model provider for tokens.
| Plan | Price | What you get |
|---|---|---|
| Open source | Free |
There is no vendor plan at all. Your only cost is what your model provider charges for tokens. |
Prices checked on Sep 6, 2026 against the vendor's pricing page. Plans change often — confirm before you pay.
Three honest limitations
- No MCP support, so it cannot use the growing set of MCP servers that Cline and other agents plug into.
- No tagged release since v0.86.0 on 9 August 2025 — commits continue, but rivals ship weekly and Aider does not.
- Terminal only: you manage context by hand with /add, and there is no visual diff view outside git.
Alternatives
- Cline — Choose Cline instead if you want the same open-source, bring-your-own-key model inside VS Code with MCP support.
- OpenCode — Choose OpenCode instead if you want a terminal agent that is still shipping releases every week and supports 75+ providers.
- Zed — Choose Zed instead if you would rather have a fast editor with agents built in than a tool that sits beside your editor.
Getting started in 5 minutes
- Install it: python -m pip install aider-install && aider-install
- Export an API key for the provider you want, for example ANTHROPIC_API_KEY or OPENAI_API_KEY.
- cd into a git repository and run aider with a model flag, for example aider --model sonnet.
- Type /add path/to/file.py, then describe the change you want in a sentence.
- Check git log and git diff; type /undo if you do not like the commit.
Aider questions
- Is Aider free?
- Yes. Aider is open source under Apache-2.0 and has no paid plan. You pay only your model provider for the tokens each request uses.
- Which models work with Aider?
- Any model reachable through LiteLLM: OpenAI, Anthropic, DeepSeek, Gemini and others by API key, plus local models served by Ollama.
- Does Aider change my code without asking?
- It applies edits and commits them, but every change is its own git commit. Review with git diff and revert with /undo or git.
- Is Aider still maintained?
- Commits continue, but there has been no tagged release since v0.86.0 in August 2025. Treat it as stable rather than fast-moving.
- Aider or Cline?
- Aider if you work in a terminal and want git-native edits; Cline if you want an editor panel, MCP support and a project that ships often.
Related reading
- DeepSeek Harness: Everything Is a Plugin
Aider is a harness with git as its memory. Seeing another harness laid out piece by piece makes its design choices legible.
Sources
- Aider documentation
- GitHub releases (last tag v0.86.0, 2025-08-09)
- Comparison of Continue, Aider and Cline (MCP support)
- Source code: Apache-2.0
Research-compiled, not hands-on tested. Compiled from official docs, the vendor's pricing page and community reviews as of Sep 6, 2026. We haven't tested it hands-on yet.