Frequently asked questions

Getting started

What is GrooveDojo?

A free drum practice app that runs in your web browser. Write grooves on a grid and read them as drum notation, hear them on a built-in kit, and practice them with a metronome, a count-in and loops. It comes with exercises, the Independence Trainer and practice plans. Connect an electronic drum kit over MIDI to see whether each hit is early or late (the editor, practicing).

Who is it for?

Drummers who practice on their own, on an electronic kit, an acoustic kit or a practice pad. Drum teachers can use it to write exercises and share them with their students (for drum teachers). I’m a hobbyist drummer, and I built it for my own practice first (about GrooveDojo).

Do I need an account?

No. There’s nothing to sign up for and nothing to install. Open GrooveDojo and start. Your library is kept in your browser (below).

Do I need an electronic drum kit?

No. Play along on an acoustic kit, a practice pad or anything else, following the click and the notation. Your runs are kept, and the Dashboard counts your practice days and minutes. Without an electronic kit there are no hits to measure, so there’s no timing feedback (practicing without a kit).

Pricing

Is GrooveDojo free?

Yes. There’s nothing to pay and no ads. If you’d like to support it, the app has a Support GrooveDojo link for an optional tip, which doesn’t unlock anything.

Will it stay free?

That’s my intention. GrooveDojo is a personal project, made to help drummers practice, and I have no plans for a paid subscription. The core practice tools are free, and they’re intended to remain free (what the Terms cover).

I cover the running costs myself. Features that cost money to run, like reading sheet music online, have usage limits and may be paused. If a future optional feature brought significant ongoing costs, I might ask a small fee to help cover it, and I’d update the Terms first. There are no plans for that now (how I keep it free).

Electronic drums

Which electronic drum kits work?

Any kit that sends MIDI over USB can be set up. GrooveDojo has been tested with a Roland TD-27KV2. Many Roland, Alesis, EFNOTE, Simmons and Yamaha modules are listed from their makers’ documents, so GrooveDojo knows their notes, but they haven’t been tested yet. For any other kit, GrooveDojo asks which kit it is, and a quick pad check sorts out the rest (the full list).

How do I connect my drum kit?

Connect the module to your computer or Android phone with a USB cable, open GrooveDojo and choose Connect kit. Allow MIDI devices when the browser asks. If your kit isn’t one GrooveDojo knows, it asks which kit it is. Then tell it how you listen in Settings, Timing (step by step).

Which browsers can connect a kit?

Kit input has been tested in Chrome on a Mac, in Firefox on a Mac and in Chrome on an Android phone. Other browsers that support MIDI, such as Edge, may work but haven’t been tested. Safari, and every browser on iPad and iPhone, can’t receive MIDI, so a kit can’t connect there, but you can still write, play and play along (Compatibility).

Why isn’t my drum kit detected?

• Check that the kit is switched on and the USB cable is plugged into the module’s USB port.
• If you blocked MIDI devices when the browser asked, allow them in the site settings (the icon at the left of the address bar), then try again.
• In Firefox, add the site-permission add-on it offers.
• A Roland TD-27 needs its USB mode set to GENERIC, and the module restarted.
• Another program may have the kit open, such as a recording app. Close it, then unplug the kit and plug it back in.

Settings, Kit & MIDI has the same steps under Troubleshooting.

Timing feedback

How does GrooveDojo measure early and late hits?

When you play on a connected electronic drum kit, GrooveDojo compares the time of each MIDI hit with the note it belongs to in the groove. It shows whether the hit was early or late, and by how many milliseconds. It works from the MIDI timestamps and the audio timing your browser provides (how drum timing is measured).

How accurate is the timing feedback?

It’s designed to help you see timing patterns: whether you tend to rush or drag, how evenly you play, and how that changes from one run to the next.

The exact early and late values can be shifted by delays in your drum kit, its connection and your audio setup. GrooveDojo can’t directly measure the moment your stick touches the pad, so the numbers aren’t laboratory measurements. For meaningful comparisons, keep the same equipment and settings (what the numbers can tell you).

Does MIDI latency affect my results?

Yes. Your drum kit and its connection take a little time to deliver each hit to the browser. A delay that stays the same shifts your early and late readings without changing how evenly your hits are spaced. A delay that varies from hit to hit can make your playing look less even than it was.

GrooveDojo uses the timing information your browser provides, but it can’t remove every source of hardware or audio delay. A consistent setup, and wired headphones or speakers rather than Bluetooth, make the feedback more reliable (tips).

How does the Improvisation Trainer check my notes when I improvise?

For each note, it finds the nearest place in the beat’s subdivision, measured from the click as in a groove, and shows whether the note fits and how early or late it was. A note that lands clearly closer to another subdivision’s place doesn’t fit. It shows where your notes landed, not which rhythm you meant (how the Improvisation Trainer works).

Practice and sharing

Can I create my own exercises?

Yes. Anything you write in the groove editor can be practiced like the built-in exercises, put in a practice plan and shared. Copy to My grooves turns a built-in exercise into a groove you can change.

Can I import exercises I already have?

Yes: a MusicXML score (.musicxml or .mxl), a MIDI file or a Groove Scribe link, or printed drum notation from a photo, a screenshot or a PDF, which is read online and can get notes wrong, so check each bar against the original (how importing sheet music works). You see what couldn’t be kept before the groove is saved (importing grooves). Only import music you have the right to use.

Can I share grooves and practice plans?

Yes. A groove, a folder or a practice plan can be shared by link or as a file, and printed. The link holds what you share, after the “#”, so it isn’t uploaded, and anyone with the link can open it. Your practice history isn’t shared.

Can teachers share exercises with students?

Yes. Write the exercises, put them in a folder or a practice plan, and send the link or a printed sheet. Students need no account. Their practice stays in their own browser, and nothing is reported back to you (for drum teachers).

Your data and privacy

Where is my practice data stored?

In your browser’s storage, on this device: your grooves, plans, practice history and settings. GrooveDojo doesn’t upload them, and they leave your device only when you export or share them. They don’t sync, so another browser or device starts empty (Privacy).

What happens if I clear my browser data?

Your library is deleted with it, and I can’t recover it, because it never reaches me. Safari may also delete a site’s data after 7 days without a visit. Export a backup now and then, from the Dashboard or Settings, Library & backup, and keep the file somewhere safe (keeping your library safe).

Does GrooveDojo upload the files I import?

No. MusicXML scores, MIDI files, Groove Scribe links and GrooveDojo files are read on your device. Sheet music is the one exception: the lines of music are found on your device, and only the lines you choose to read are sent, through GrooveDojo, to Anthropic to read the notes. The rest of the image stays on your device, and GrooveDojo doesn’t keep the lines (Privacy).

Does it work offline?

After your first visit, GrooveDojo can open and play without a connection. This has been tested in Chrome on a Mac, with GrooveDojo installed from Chrome. Reading sheet music needs a connection. Other browsers haven’t been tested offline yet (working offline).

Still have a question?

Write to me at the contact address at the foot of this page. I read every message.