joshpxyne/gpt-migrate

GPT-Migrate is a command-line tool that uses a large language model to automatically rewrite a codebase from one programming language or framework into another. You point it at a folder of source code and tell it the target language, and it does the translation work by repeatedly asking the AI to read and rewrite each file. The process has several stages. First the tool sets up a Docker container, which is an isolated software environment, configured for the target language. Then it reads your existing code to identify which third-party libraries you are using, finds equivalent libraries in the new language, and begins rewriting the code file by file starting from your application's main entry point. Once the new code is written, it starts the application in the container and runs automatically generated tests against it. If anything fails, the tool reads the error messages and attempts to fix the code on its own, repeating until the tests pass or the user intervenes. The tool is designed to work with GPT-4 and is configured by default to use GPT-4-32k, a version with a larger context window useful for reading longer files. It also supports connecting through OpenRouter, a service that routes requests to multiple AI providers. Running a full migration can accumulate significant API costs because the model may need to rewrite and debug large amounts of code. Configuration is done through command-line flags specifying the source directory, source language, target language, entry point file, and other options. A set of benchmark examples is included in the repository for testing, including a sample Flask-to-Node.js migration. The README notes that results should not be trusted blindly and that the tool should be used with care, particularly for large codebases where costs and errors can compound.