Aider
Open-source AI pair programming tool that runs in the terminal, edits local code, and keeps changes inside normal git workflows.
About Aider
Aider is an open-source AI pair programming tool for developers who want an AI coding assistant inside the terminal rather than inside one specific editor. The official site describes it as a way to pair program with LLMs to start a new project or build on an existing codebase. Its strongest fit is repository-aware coding work where the developer wants to choose a model provider, select files, ask for changes, inspect diffs, and keep the result in ordinary git history. Aider maps the repository so the model can understand related symbols, integrates with git so edits are committed and undoable, and can run linting or tests after changes. It also supports workflows beyond a plain command prompt, including AI comments from an IDE, images and web pages as context, local models, OpenAI-compatible APIs, and provider-specific API keys. The software is free and Apache 2.0 licensed, but most serious hosted-model use still depends on external model accounts, API keys, token costs, data-handling terms, and model capability. Aider is a strong fit for terminal-native developers and teams that want local control; it is a weaker fit for teams that need a managed cloud agent, visual IDE-first collaboration, centralized policy controls, or a vendor-provided enterprise support plan. Working in an existing repository? Use [Aider vs Cursor for Git-controlled work](/en/articles/aider-vs-cursor-git-controlled-repository) to compare context selection, dirty-worktree handling, diff review, commits, and recovery.
Best for
Best use cases
Implement a small feature inside an existing git repository, let Aider edit the selected files, then review the generated commit and diff before pushing.
Refactor a multi-file module while using the repository map to give the model context about related classes, functions, and call signatures.
Run a failing test or linter after an AI edit, feed the failure back into the same terminal session, and ask Aider to repair the change.
Work over SSH, tmux, a cloud dev box, or a minimal terminal environment where a full AI IDE extension is unavailable or inconvenient.
Compare coding performance across Claude, OpenAI, Gemini, DeepSeek, OpenRouter, local models, or OpenAI-compatible endpoints without changing the editing workflow.
Compare before choosing
Compare with editor-native tools such as Cursor or GitHub Copilot when inline completions, GUI review, and IDE-integrated chat matter more than terminal portability.
Compare with cloud software-engineering agents when you want background task execution, hosted sandboxes, pull-request automation, or managed review queues.
Compare with general chat tools when the main need is explanation or planning, but choose Aider when edits should be applied directly to local files.
Compare with local-model workflows such as Ollama plus a custom script when privacy and offline operation matter more than Aider's built-in git, repo-map, and command UX.
Features
Terminal-based pair programming
Aider runs from the command line, lets developers name files to add to the chat session, and applies requested code changes directly to local project files.
Model-flexible LLM access
Official docs describe connections to many hosted and local models, including OpenAI, Anthropic, Gemini, DeepSeek, OpenRouter, OpenAI-compatible APIs, Ollama, and other LiteLLM-supported providers.
Repository map context
Aider builds a concise map of the git repository, including important classes, functions, types, and call signatures, so the model can reason about code outside the immediate files in chat.
Git-integrated change control
Aider is tightly integrated with git, can commit edits with descriptive messages, supports undo and diff review, and takes care around dirty files before applying its own changes.
Linting and testing loop
Aider can automatically lint and test code after it makes changes, and developers can configure custom lint commands or test commands for project-specific verification.
IDE comment workflow
With watch mode, Aider can read AI instructions written as comments in an editor and respond to change or question triggers while preserving a terminal-driven workflow.
Images and web pages as context
Official usage docs explain that developers can add screenshots, mockups, error images, and URLs to the chat for supported models and documentation-heavy tasks.
Privacy-aware analytics controls
Aider's analytics docs say analytics are opt-in, anonymous, and do not collect code, chat messages, keys, or personal information, with a documented command to disable analytics.
Pros
- Free Apache 2.0 open-source software with an official GitHub repository and public documentation.
- Works in terminal environments where editor-specific AI extensions may not be available, including remote shells and lightweight dev boxes.
- Keeps AI edits inside normal git review habits, including diffs, commits, undo flows, branches, and external git tools.
- Supports a broad range of model providers and local-model routes instead of locking the workflow to one hosted coding model.
- Repository maps, linting, testing, image context, web-page context, and IDE comment triggers make it more capable than a simple chat wrapper.
Cons
- The software is free, but most productive hosted-model use still requires separate API keys, provider accounts, token budgets, and provider-specific data terms.
- A terminal-first interface can be less approachable for developers who prefer inline IDE completions, visual file trees, and GUI review panels.
- Aider is not a managed cloud engineering agent; it does not by itself provide hosted sandboxes, queued background tasks, or organization-wide admin controls.
- Model quality matters: the official docs warn that weaker models may fail to return usable code edits, so results depend heavily on model choice.
- Teams handling sensitive code still need to evaluate the selected LLM provider, local model setup, analytics settings, and internal policy before adoption.
Pricing Plans
Open-source Aider software
- Apache 2.0 licensed open-source project
- Terminal coding assistant for local git repositories
- Repository map, git integration, lint/test hooks, and configuration support
- Install options documented for aider-install, uv, pipx, pip, Docker, Codespaces, and related routes
External model/provider usage
- Most hosted models require an API key or provider account
- Costs depend on selected model, token volume, rate limits, and provider plan
- Free provider options and local models may reduce software spend but can have capability or quota limits
- Provider privacy, retention, regional availability, and support terms should be checked before using private code
* Pricing information is for reference only. Please refer to the latest announcement on Aider's official website.