Aider

Terminal-based AI coding tool that edits an existing codebase and works with Git and chosen model providers.

Select the files and model, describe a small change, and inspect the diff and tests before continuing.

Access and pricing: The software is free to use. Model API access or local inference requires its own account, hardware, and associated costs.

Try this task: Make one reversible code edit Start in a disposable Git checkout and request a small validation fix with the existing test command.

Check the result: Inspect changed and new files, run a known failing input, and verify that reverting the task preserves unrelated work.

Choose carefully: Model-provider setup and usage costs are separate from the local coding workflow.

Evidence: This is an editorial exercise based on the documented product scope, not a recorded hands-on product benchmark. Use permitted or fictional inputs and record your own observed result.

What it does well

Aider is a terminal tool that edits your codebase through chat. According to its usage documentation, it commits every change to git, so edits are easy to track and undo, and the /undo command reverts changes you do not want. It can connect to almost any model, including local ones, with dedicated pages for OpenAI, Anthropic, Gemini, Groq, LM Studio, Ollama, OpenRouter, Azure and Amazon Bedrock.

Getting started in 10 minutes

Follow the installation guide, then start aider with the files you want to change, for example aider file1 file2. Describe the change at the prompt. Add only the files that need editing, since aider pulls in related context from the repository. Use /add to include more files and /model to switch models mid-session.

Limits to check before you commit

The software is free, but you pay your model provider (or run local models on your own hardware). The usage page did not state the license or supported operating systems, so check the project's GitHub page. Always review diffs and run your tests before continuing.