AudioMass

AudioMass is a free browser-based audio editor that feels a bit like Audacity, but runs entirely online. You can record, edit, trim, layer, and apply effects to audio without installing anything, making it surprisingly powerful for a web app.

It also supports multitrack editing, sample projects, and a growing collection of tools for music, podcasts, sound effects, and general audio work. Best of all, it’s open source, so you can explore how it works or even contribute to its development yourself.