About Transmute

A free collection of browser-based file conversion and developer tools. Every tool runs on your device using WebAssembly and modern browser APIs. Your files are never uploaded to a server.

Why it works this way

Most online converters ask you to upload a file, wait in a queue, and trust them with it. Transmute does the work in your tab instead. That means faster results, no queue, and nothing to sign up for — because there is no account and no data to hand over.

What it does not mean is no limit. There is no upload limit, because there is no upload — but a browser tab has a ceiling of its own, and the honest thing is to name it. 106 of the 152 tools that take a file take one of any size. 11 enforce a 1.5 GB cap and print it on the drop zone before you pick anything, and 35 more hold the whole file in memory to do their work and say so on the page rather than promise otherwise.

What you can do

IMAGEConvert between HEIC, WebP, PNG, JPG, AVIF and TIFF

IMAGECompress, resize and crop with real quality control

PDFMerge, split, compress, rotate and reorder pages

AUDIOConvert and trim MP3, WAV and M4A, or merge tracks

VIDEOConvert to GIF, trim clips, extract audio, compress

DEVFormat JSON, SQL and XML; encode Base64 and URLs

DEVGenerate UUIDs, passwords, hashes, QR codes, lorem ipsum

DEVBuild CSS gradients and box shadows, pick colours

How it is built

Next.js and TypeScript, exported as a fully static site. The heavy lifting is done by FFmpeg.wasm, pdf-lib, pdf.js, qpdf, the Canvas API, Web Audio and WebCodecs. Because everything compiles to static HTML, CSS and JavaScript, there is no backend — and therefore nothing that can leak your files. 190 tools ship this way today.

Built by

Transmute is built and maintained by Ishank. Feedback and feature requests are welcome.