Privacy Policy

Last updated: 26 April 2026

Your audio files

Audio files you drop into mp3tom4b are processed entirely in your browser via WebAssembly. They are never uploaded, transmitted, stored, or shared. The only place they exist outside your device is wherever you choose to save the resulting M4B.

Cover images and metadata

Cover images and the metadata you type (title, author, narrator, year, genre) are also processed only in your browser and end up only in the M4B file you download.

Analytics

We use Vercel Analytics to count anonymous page views. It does not set cookies, does not identify visitors, and never receives any of your audio, metadata, or cover images. No third-party advertising trackers are loaded.

External resources

On first use, your browser downloads the FFmpeg WebAssembly core from a public CDN (unpkg.com). This is a one-time fetch of a publicly available binary; no data about you or your files is sent in the request.

Cookies

mp3tom4b sets no cookies. No login. No account. Nothing to consent to.

Contact

Operator: Burcevski ICT (KvK 74404172), Amersfoort, the Netherlands.
Email: sebas.bur@gmail.com