Convert, clean, visualize your data and edit PDFs — entirely in your browser. Your files never leave your device. Ever.
Muffin is a free collection of browser-based data tools built for researchers, data scientists, students, and developers who are tired of uploading files to random websites just to do a simple task. Every tool on Muffin runs entirely in your browser — your files never leave your device, nothing is stored on any server, and no account is required. Ever.
Most online converters and data tools upload your file to a remote server to process it. That means your research data, confidential documents, API keys accidentally left in notebook outputs, or proprietary datasets are transmitted to a third party — often stored, logged, or used to train other systems.
Muffin processes everything locally using your browser's built-in JavaScript engine. The file is read into memory, processed, and downloaded — all without a single byte leaving your machine. You can disconnect from the internet after the page loads and every tool will still work perfectly. No account, no email, no paywall, no file size limit, no "upgrade to Pro" popup.
Muffin was built by researchers for researchers — but anyone who works with data will find it useful. If you have ever needed to quickly convert a CSV to JSON before loading it into a Python script, clean a Colab notebook before pushing to GitHub, visualize an experiment log without opening Matplotlib, fill a PDF form without creating an account, or merge your lecture PDFs into one file — Muffin is built for exactly those moments.
Muffin is and will remain free. There is no freemium tier, no file size limit behind a paywall, no "export requires Pro". The tools are HTML, CSS, and JavaScript — they cost virtually nothing to run. Built by Sneha Chakraborty and Divyansh Pathak because we needed these tools ourselves and got tired of the alternatives.