Audiomass: A Free Open-Source Multitrack Audio Editor for Web

Audio editing on the web has long been a second-class experience—clunky interfaces, limited capabilities, and reliance on native apps like Audacity or Ableton. Now Audiomass is flipping that narrative with a full-featured multitrack editor that runs entirely in your browser. The response on Hacker News has been enthusiastic, and after spending time with it, I can see why.

Audiomass: A Web-Based Multitrack Editor

Audiomass is a free, open-source multitrack audio editor for the web. It supports importing and arranging multiple audio tracks, applying effects, and exporting the final mix—all within a browser window. The design is clean and modern, taking clear inspiration from Audacity but with a more refined user experience. The project was submitted to Hacker News by its creator, pantelisk, and quickly gathered 93 points and 24 comments.

The tool leverages the Web Audio API to process audio client-side, meaning no server uploads or downloads for basic editing. You can import local files, cut, copy, paste, and adjust volume and pan per track. It’s surprisingly responsive for something running in a sandboxed browser environment.

Why HN Is Excited

The Hacker News thread reveals a mix of excitement and feature requests. One commenter captured the broader vision:

“I want to 'check out' someone's drum loop and add a guitar riff. Check it into a branch. Someone else checks out the drum+guitar, adds a bass line. Checks in.”

This desire for collaborative, version-controlled audio editing—dubbed “RiffHub”—is clearly on many people’s minds. Audiomass comes tantalizingly close to being the foundation for such a tool, but it currently lacks any cloud synchronization or multi-user features.

Other feedback focused on polish: tooltips on deactivated buttons, support for obscure formats like XM (a tracker module format), and general UX improvements. The creator responded to some comments, showing active engagement with the community.

The Gap: Cloud Collaboration

Audiomass is an impressive technical achievement. The Web Audio API has matured to the point where real-time multitrack editing is not just possible but smooth. Being open-source (license not explicitly stated on the site, but the HN post says “open-source”) means developers can inspect, fork, and improve it.

What strikes me is the gap between what Audiomass is today and what it could be. The comment about “RiffHub” highlights a massive unmet need: collaborative music creation on the web. We have Google Docs for writing, Figma for design, and GitHub for code—but nothing comparable for audio. Audiomass, with its core audio engine, is a perfect starting point for that vision. However, implementing real-time collaboration—let alone version control for audio—is enormously complex. Audio files are large, latency matters, and conflicts are messy.

Still, Audiomass proves the foundation is solid. The choice to stay client-side avoids cloud costs and privacy concerns. For a solo musician or podcaster, it might already be a viable alternative to Audacity for simple edits.

What This Means for Developers

Audiomass is a great case study for building audio or creative tools on the web. Here are a few takeaways:

The Web Audio API is ready. You can do real-time effects, mixing, and multitrack playback entirely in the browser. Here’s a minimal example of loading two audio files and playing them simultaneously:

const audioContext = new AudioContext();
const buffer1 = await fetch('track1.mp3').then(r => r.arrayBuffer());
const buffer2 = await fetch('track2.mp3').then(r => r.arrayBuffer());

const source1 = audioContext.createBufferSource();
source1.buffer = await audioContext.decodeAudioData(buffer1);
source1.connect(audioContext.destination);
source1.start();

const source2 = audioContext.createBufferSource();
source2.buffer = await audioContext.decodeAudioData(buffer2);
source2.connect(audioContext.destination);
source2.start(0);

For more advanced use cases like real-time effects and low-latency processing, use AudioWorklet.

Offline support is still tricky. Audiomass currently requires an internet connection to load, but once loaded, it could cache its assets via a Service Worker. That would make it usable off-grid—a nice UX win.

The UX gap is real. The feedback about missing tooltips on disabled buttons is a small but telling detail. For audio editors, discoverability matters. If a button is disabled, tell me why. This is something Audacity does well, and Audiomass should emulate.

Format support matters. The request for tracker module formats (like XM) shows there’s a niche but passionate community that wants web-based tools for retro music production. Supporting those formats could be a differentiator.

Should You Care?

If you’re a musician or podcaster looking for a lightweight, no-install audio editor for quick edits, Audiomass is worth a try—especially if you value open-source and are tired of Audacity’s dated interface. If you need cloud collaboration, version-control, or advanced effects (like compression, reverb, or equalization), this isn’t ready yet. But if you’re a web developer curious about the limits of the Web Audio API, Audiomass’s code is an excellent resource. The project is young, so expect bugs, but the trajectory is promising.