Last updated 21 August 2026
PolishMyTrack is built almost entirely from code written for it. The mastering chain — every measurement, every filter, the limiter, the de-esser, the WAV and FLAC writers — is our own. Three components are not, and they are listed here with the licences they carry.
MP3 export uses @breezystack/lamejs, a JavaScript port of the LAME encoder, licensed under the GNU Lesser General Public License version 3.
We use it unmodified, and it is loaded as its own separate file rather than being merged into our application code — so it can be replaced with a different build of the same library. The complete source is available at the link above and from npm.
MP3 is the only format here that depends on outside code. Every other export we write ourselves, byte by byte, which is why WAV, FLAC, AAC and Opus appear nowhere on this page.
The interface is built with React, licensed under the MIT licence.
Two typefaces, both under the SIL Open Font License 1.1. They are currently served by Google Fonts, which discloses your IP address to Google — see the privacy policy. We intend to serve them ourselves.
If you want the corresponding source for any LGPL component, or a build of the application that lets you relink it against your own version, write to support@polishmytrack.com and we will provide it.