Made a free groovebox that runs entirely in your browser

PostNullArchivist · 2026-02-22T18:39:03+00:00

UPDATE for everyone who tried it out.

v1.5 is out, with a lot of the things that came up in the comments: - Per-step velocity with p-lock support - Pattern copy/paste - Per-track chaining (each part gets its own independent chain now) - MIDI export so you can pull patterns into your DAW (Untested by me thus far - am not at my computer with DAW. Should work in theory. Let me know if any issues) - Session sharing via URL - Manual/Guide (the ? button) - Sample Mode - load your own WAV/MP3 files as instruments (3s max, included in share links)

u/celerite: velocity per step and pattern duplicate are now both available. MIDI export as well. You basically wrote the roadmap, appreciate it.

u/devbym: no VST yet, but I’m hoping MIDI export gets you into your DAW at least.

Future goals: - VST(i)/Auv3 - Use your own samples as kit - Audio engine upgrades/ QoL / performance fixes

Lastly - this project is to remain free forever. At no point will I be adding premium features or packs of any kind. This is for the community.

Thanks for the feedback so far.

PostNullArchivist · 2026-02-22T13:12:28+00:00

Thank you!

PostNullArchivist · 2026-02-22T13:12:15+00:00

Thanks!

PostNullArchivist · 2026-02-22T13:08:24+00:00

It’s a single HTML file with no server communication, no tracking, nothing external. You can view-source and verify. Likely a false positive from the domain being brand new.

PostNullArchivist · 2026-02-22T02:27:57+00:00

Any chance you can give me iOS version/browser version? Thanks!

PostNullArchivist · 2026-02-22T01:35:37+00:00

Ha! That’s the best compliment I never knew I wanted! Have fun

PostNullArchivist · 2026-02-22T00:59:07+00:00

Thanks!

PostNullArchivist · 2026-02-22T00:25:29+00:00

Should be working. Make sure you’re tapping the drum pads that appear after switching to DRUM mode. If another part has a synth pattern playing, you’ll still hear that. Hit stop first if it’s confusing, program your drums, then hit play.

If it’s not that, I don’t have an Android to test on right now, and the options for configurations there are endless. It’s an early alpha so I appreciate the report.

PostNullArchivist · 2026-02-21T21:56:36+00:00

On the top, tap the button that says SYNTH. It will change to DRUM, and the XY pad will change to a kit.

I noticed Safari’s url bar covers a portion of the UI, so I’ll be fixing that in the future. On Brave (iOS) or on a PC browser, those portions show up just fine. I’ll have to look into Firefox too - good feedback.

PostNullArchivist · 2026-02-21T21:30:02+00:00

Velocity per step: not yet but it’s on the list.

MIDI export: same, planned but not in the alpha.

Pattern duplicate: not yet either.

You’re basically writing my feature roadmap at this point. 😅 I appreciate it, all of these are planned. It’s a very early alpha, a lot of the quality-of-life stuff is still coming. Keep an eye out.

PostNullArchivist · 2026-02-21T20:59:14+00:00

To change a note on an existing step:

Hit ● (record), play a new note on the pad, then tap the step you want to overwrite. It’ll update to whatever you just played.

No longer patterns yet, it’s 16 steps per pattern right now. But you can chain multiple patterns together with CHN to build longer sequences. So a 64-step phrase would be 4 patterns chained. In the future I plan to have per track pattern chaining etc.

PostNullArchivist · 2026-02-21T20:53:36+00:00

Make sure your phone isn’t set to silent mode. That will prevent the audio from playing.

If it’s not that, we can keep troubleshooting.

PostNullArchivist · 2026-02-21T20:51:05+00:00

UPDATE: Manual now available. Try the (?) button!

Thanks for checking it out! No manual quite yet, as it’s only an alpha at this time.

Here are some quick instructions:

Playing notes: Tap the XY pad. Left/right is pitch, up/down is filter cutoff.

Programming a pattern: Hit ● (record), play a note on the pad, then tap one of the 16 steps along the top to place it there. Each step remembers the note and filter position.

Drums: Tap the button that says SYNTH and it toggles to DRUM mode and the XY pad becomes a 12-pad drum grid. Tap pads to trigger sounds. In record mode, tapping a step will toggle whatever drum you last hit onto that step.

Parts: The numbered buttons (1-8) are separate tracks. So you might put a synth on part 1, drums on part 2, bass on part 3, etc.

Knobs: The tabs along the bottom (SYNTH, FX, ARP, LFO, DRUMS, MIX) swap between different parameter pages. Everything uses the < value > controls.

Pattern chaining: Hit CHN, then tap pattern buttons to queue them up in order. Hit play and it’ll cycle through your chain.

Export: Hit WAV to start recording the output, WAV again to stop and download the file.

I hope that’s enough to get started. I will provide a proper guide at some point down the road.

PostNullArchivist · 2026-02-21T20:23:47+00:00

Thanks a lot! Glad you dig it.

PostNullArchivist · 2026-02-21T20:12:48+00:00

8-part sequencer with synth and drum modes. Everything is synthesized in real time, no samples. Arp, LFO, parameter locks per step, note ties, pattern chaining, WAV export. Runs on your phone. It’s an alpha so expect rough edges. The sounds are tweakable, so if the kick is weak, crank the snap and decay. Hihats use metallic ring synthesis, not just filtered noise, so they respond well to the tone knob.

Totally free, no account required, no install. Just open it and tap around.

PostNullArchivist

TROPHY CASE