Aider (aider.chat) is an open-source AI pair-programming tool that runs in the terminal and via a browser chat. It pairs your codebase with LLM "copilots" to make context-aware edits, run linters/tests, and commit sensible changes to git. Primary values are repository mapping to provide models wider context, multi-LLM support (OpenAI, Anthropic, DeepSeek, local models and more), and git integration so AI-generated edits are applied as commits you can diff and undo. Key features described in the documentation include multi-LLM model switching, a repository map that builds concise context for models, support for diffs and whole-file edits, automatic commit creation with sensible messages and undo support, IDE/editor integrations (including comments-based use and Codespaces), quality workflows that can run linting/tests and fix issues, attachments and input such as images and web pages for visual context, voice interactions, prompt caching for some providers, exhaustive CLI configuration (model selection, API keys, caching, repo map behavior, git handling, theming, debugging), and scripting/automation via CLI or Python for integration into workflows (e.g., GitHub Actions). The project is open-source (GitHub: https://github.com/Aider-AI/aider) under Apache 2.0. Documentation pages include installation, CLI options reference, usage guide, repomap docs, leaderboards/benchmarks, advanced model settings, git integration docs, privacy policy, and release history. The site contains no explicit hosted product pricing or free-trial information; the available content focuses on open-source tooling and documentation. Recommended next steps are following the install docs to try locally, reviewing CLI options and advanced model settings to configure models and costs, and cloning the GitHub repo for examples and contribution guidance. If details about hosted/paid offerings are needed, the documentation suggests contacting the community (Discord) or opening a GitHub issue to confirm.