Refact.ai - Your Customizable Open-Source AI Software Engineering Agent
Refact.ai is the #1 free open-source AI Agent on the SWE-bench verified leaderboard. It autonomously handles software engineering tasks end to end. It deeply understands large and complex codebases and integrates with developers’ tools (including MCP), databases, and browsers to automate complex, multi-step tasks.
- Integrate the AI Agent with the tools you already use, allowing it to complete tasks end to end while transparently showing every step it takes.
- Access state-of-the-art models like Claude 4 Sonnet, GPT-4.1, 4o, Gemini 2.5 Pro, and more.
- Bring your own key (BYOK) or connect local providers.
- Stop switching between your IDE and chat—Refact.ai has an integrated chat right in your IDE.
- Get free, unlimited, context-aware auto-completion.
Suitable for both individual and enterprise use, supporting 25+ programming languages, including Python, JavaScript, Java, Rust, TypeScript, PHP, C++, C#, Go, and more.
We can't say it better than our users: 'Refact.ai understands me better than my human coworkers. It's like working in perfect sync with an ideal partner.'
How does Refact.ai Agent empower developers?
- Unlimited accurate auto-completion with context awareness for free - Powered by Qwen2.5-Coder-1.5B, Refact.ai uses Retrieval-Augmented Generation (RAG) to provide precise, context-aware code suggestions. By retrieving relevant snippets and project-specific insights, it ensures completions that align with your coding style and architecture.
- Integrated in-IDE Chat - By deeply understanding your codebases, Refact.ai provides relevant, intelligent answers to your questions—right inside your development environment.
- Integrated with the tools - Refact.ai goes beyond codebases, connecting with GitHub, GitLab, databases (PostgreSQL, MySQL), Pdb, Docker, and any shell command, so AI Agent can autonomously complete tasks—from code generation to deployment.
- State-of-the-Art Models - Refact.ai supports Claude 3.7 Sonnet, GPT-4o, and o3-mini, allowing you to choose the best model for each task based on its complexity.
- Bring your own key (BYOK) - Use your own API keys for external LLMs, ensuring flexibility and control over your AI infrastructure.
- Upload images: Click the image button to add visual context to your chat.
- Use @-commands to control what context to use to answer your question:
- @web - define a webpage.
- @file - upload and attach a single file.
- @definition - find and attach a definition.
- @references - locate all references and attach them.
- @tree - display the workspace directory and files tree.
- Create your own custom system prompt for a more personalized workflow.
BYOK/local-only setup
Refact runs with BYOK or local model providers configured on your machine.
Open the Refact sidebar, configure at least one provider in Provider Setup, then choose default models.
Which tasks can Refact.ai help me with?
Generate code from natural language prompts (even if you make typos) - Instantly turn ideas into functional code, accelerating development and eliminating the blank-screen problem.
Refactor code - Improve code quality, readability, and efficiency with automated refactoring that aligns with best practices.
Explain code - Quickly understand complex or unfamiliar code with AI-generated explanations, making collaboration and onboarding faster.
Debug code - Detect and fix errors faster with intelligent debugging, reducing time spent troubleshooting issues.
Generate unit tests - Ensure code reliability by automatically creating comprehensive unit tests.
Code Review - Get AI-assisted code reviews for cleaner, more secure, and more efficient code, addressing developers' top concern: accuracy.
Create Documentation - Automate documentation generation to keep knowledge accessible and up to date.
Generate Docstrings - Enhance maintainability with clear, structured documentation generated for functions and classes in seconds.
Support & Feedback
Use GitHub issues or discussions to ask questions, report bugs, or propose features.
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