Music tools that run in your browser

One workflow, three small tools

xx808 is built around a common studio errand: you hear something you like and want to work with it. Start with the BPM & key finder to learn the reference track’s tempo and key. Pull its melody, chords or bass line out as notes with the audio to MIDI converter, which uses that tempo so the notes snap to the right grid. Then open the drum machine at the same tempo, with the 808 kick already tuned to the key, and sketch a beat around it. Each step exports a standard file — MIDI or WAV — that you can drag straight into Ableton Live, FL Studio, Logic Pro, GarageBand or any other DAW.

Each tool also stands on its own. If you only need to know whether a song is 92 or 94 BPM before you DJ it, the tap tempo pad works with a space bar or a thumb. If you only need a quick sixteen-step pattern to play over, the drum machine starts in one click.

Private by design

Most online audio tools upload your file to a server, process it there, and send a result back. That costs the site money, which is why so many of them add sign-ups, daily limits and paid tiers — and it means a copy of your unreleased music sits on someone else’s computer. xx808 works differently. The page downloads the code once, and from then on your browser does all the processing: decoding the audio, running the note-transcription model, measuring tempo and key, and synthesizing drum sounds. There is no upload step at all.

Want proof? Open the Network panel in your browser’s developer tools and run any of the tools. You’ll watch the page and its scripts arrive — plus, for the MIDI converter, a model file of about 1 MB. The only thing that ever leaves your device is an anonymous, cookieless page-view ping from Cloudflare Web Analytics (a small script from static.cloudflareinsights.com and one request to /cdn-cgi/rum), and your audio is never in it. With a tool page already open (and, for the MIDI converter, its model already fetched), a dropped connection doesn’t interrupt your work.

What’s under the hood

• Note transcription uses Basic Pitch, an open-source neural network released by Spotify’s Audio Intelligence Lab, running with TensorFlow.js in a background thread.
• Tempo and key detection use classic signal-processing methods — onset detection with autocorrelation for tempo, and pitch-class profiles matched against the Krumhansl–Kessler key profiles for key — implemented in plain TypeScript.
• Drum sounds are synthesized from oscillators, noise and envelopes with the Web Audio API, the same way the analog machines of the early ’80s made them. No sample packs, so no licensing questions about what you export.
• Files you export are standard: MIDI format 1 at 480 ticks per quarter note with the tempo included, and 16-bit 44.1 kHz WAV.

Who it’s for

Bedroom producers who want a melody from a voice memo as MIDI. DJs checking tempo and key before building a set. Guitarists and pianists who want to see the notes of a riff. Beatmakers who need a quick 808 pattern at a specific tempo on a laptop that doesn’t have their DAW. Teachers who want a free drum machine students can open on a school Chromebook without installing anything.

What xx808 isn’t

It isn’t a full DAW, a stem splitter or a sheet-music engraver, and it doesn’t try to be. The tools are deliberately small and quick to load. Automatic transcription and detection are estimates, so check results by ear — the tools are designed to make that easy, with previews, half/double tempo switches and adjustable thresholds.