The short version
- It's a free online music sequencer with four parts: drums, bass, chords and lead. No signup, no download, no “upgrade to export”.
- Scale lock is on, always. Every row is a note from your key, so any square you light fits. Change the key and the whole loop moves with it.
- The recipe: kick on 1, snare on 2 and 4, a chord every half bar, bass on each chord's root, and a short melody with gaps.
- Safe chords: I–V–vi–IV in major (C G Am F), i–VI–III–VII in minor (Am F C G). The chord rows are labelled, so just read and tap.
- Take it anywhere: WAV for your video editor, multi-track MIDI for any DAW, or a link for your mates.
- The Suno button writes a style prompt from your loop (genre, BPM, key, progression, instruments, groove) and opens it in the Prompt Studio.
How to make a loop in five minutes
- Load a starter from the menu, or pick a key and scale. Not sure? A minor sounds moody and nobody will ever ask why.
- Drums first. On the 🥁 tab: kick on step 1, snare on 5 and 13 (beats 2 and 4), closed hats on every other step. That's 90% of pop music, you're welcome.
- Chords next. On the 🎹 tab, put a chord on step 1 and step 9 of each bar. Each chord rings until the next one. Four chords across two bars is the classic shape.
- Bass follows the chords. On the 🎸 tab, put the bass on the same letter as the chord (the chord rows tell you: vi · Am means play an A). Line it up with the kick and the low end suddenly sounds expensive.
- A melody, but a small one. On the ✨ tab, a few notes, lots of space, finish on the glowing root row. You can't hit a wrong note, so experiment freely.
- Feel. Nudge BPM for the genre, add 15–25% swing for hip-hop and lo-fi, leave it at 0 for house and pop.
- Keep it. WAV, MIDI, a share link, or straight into Suno via the prompt panel.
Stuck? Press Surprise me. It doesn't throw random notes at the wall: it picks a real chord progression for your scale, puts the bass on the roots and writes a melody from chord tones. Roll until something makes you grin, then fix the bits you don't like.
What each part does
| Part | Its job | Start with |
|---|---|---|
| 🥁 Drums | The pulse. Six synthesised voices: kick, snare, clap, closed hat, open hat and rim. | Kick on 1 and 3, snare on 2 and 4 |
| 🎸 Bass | Glues the drums to the harmony. Eight in-key notes from the root up an octave. | The root of each chord, on the kick |
| 🎹 Chords | The mood. Seven rows, one per chord that fits your key, each labelled like IV · F. | One chord every half bar |
| ✨ Lead | The bit people hum. Ten in-key notes across about an octave and a half. | Three or four notes, then silence |
Keys and scales, minus the music-theory homework
A key is the “home” note your song keeps coming back to. A scale is the set of notes that sound good together around it. This sequencer only gives you notes from the scale you pick, which is why it's so hard to make it sound bad.
| Scale | Sounds | Great for |
|---|---|---|
| Major | Bright, happy, sing-along | Pop, country, afrobeats |
| Minor | Moody, emotional, night-drive | Lo-fi, house, synthwave, most of my songs |
| Dorian | Minor, but cooler and a bit jazzy | Boom bap, funk, neo-soul |
| Mixolydian | Major with a bluesy swagger | Rock, classic funk, jam bands |
| Harmonic minor | Dark, dramatic, a little exotic | Trap, drill, film villains |
| Major pentatonic | Five notes, impossible to mess up | Melodies, kids' songs, folk |
| Minor pentatonic | Five notes, instant guitar-solo energy | Blues, rock leads, hooks |
Want to understand the chords in more depth, with guitar shapes and a piano view? The chord progression generator picks progressions by mood, and the online piano keyboard names any chord you hold.
Turning your loop into a Suno prompt
This is the bit I built the whole thing for. Suno is brilliant at producing a song, but you have to describe it in words, and “sad but bouncy, you know, like that one song” doesn't cut it. The prompt panel reads your actual loop and writes something like:
lo-fi hip hop, 78 bpm, warm sub bass, rhodes electric piano, bell melody, relaxed, nostalgic, key of A minor, i–VI–III–VII progression (Am F C G), backbeat snare on 2 and 4, swung groove
Copy it into Suno's Style of Music box, or press Open in Prompt Studio to tweak the mood, instruments and vocals first. AI models don't follow an exact chord chart reliably, but naming the key, tempo and progression nudges them a long way closer to the thing in your head. My guide on writing Suno style prompts explains why the order matters, and the BPM cheat-sheet helps you pick the tempo.
WAV, MIDI and share links
- WAV renders your loop (twice, for 1 and 2-bar loops) as a 16-bit stereo file. Drop it into a video editor, a DAW or a sampler.
- MIDI gives you the notes, not the sound: one track each for drums, bass, chords and lead, with the tempo built in. Drums use General MIDI numbers on channel 10, so they open as drums in GarageBand, FL Studio, Ableton, Logic or BandLab.
- Copy loop link squeezes the whole loop, every note, sound and setting, into the URL. Send it, and they hear exactly what you made.
Step sequencer vs piano roll vs DAW
A step sequencer (this) is a grid of equal steps: fast, fun and very hard to get lost in. A piano roll is a timeline where notes can be any length and start anywhere: more flexible, more fiddly. A DAW is the whole studio, with audio recording, mixing and arranging. Most producers sketch in a sequencer and finish in a DAW, which is exactly what the MIDI export is for. I wrote a plain-English explainer on what a music sequencer is if you'd like the longer version, and a round-up of the best free online music makers for when you outgrow this one.
How it works, and what it does with your data
There are no audio files on this page. Every sound is synthesised as it plays: the bass is a sine or sawtooth through a filter, the electric piano is a pair of sine waves with a bright “tine” on top, the pad is two detuned sawtooths, and the drums are the same oscillator-and-noise kit as my drum machine. Notes are scheduled on the audio clock a tenth of a second ahead, so the groove stays tight even when your browser is busy.
Nothing you make leaves your device. No account, no uploads, no microphone. Your loop lives in your own browser storage and in any link you choose to copy.
Online music sequencer FAQ
What is an online music sequencer?
A browser tool that plays musical events on a repeating grid. Each bar is split into 16 steps; switch a step on and that drum or note plays there. This one has drums, bass, chords and a melody, so you can build a complete loop without installing anything.
Is it really free?
Yes. No account, no trial, no export limits, no watermark. WAV and MIDI files are made in your browser.
Step sequencer or piano roll: what's the difference?
A step sequencer is a grid of equal steps that are on or off: quick for drums and loops. A piano roll lets notes be any length and start anywhere. This tool is a step sequencer with piano-roll-style note rows, and notes can ring until the next one.
What does scale lock mean?
The grid only offers notes from your chosen key and scale. Every square fits with every other square, and changing the key moves the whole loop.
Can I export MIDI?
Yes, a multi-track MIDI file with tempo, drums on channel 10 (General MIDI), and separate bass, chord and lead tracks. It opens in any DAW.
How do I get my loop into Suno?
Use the Suno panel under the grid. It writes the style prompt from your loop; copy it into Suno's style box, or press Open in Prompt Studio to edit it first.
Which chords should I start with?
Major key: I–V–vi–IV (C G Am F). Minor key: i–VI–III–VII (Am F C G). One chord every half bar over two bars.
Does it work on my phone?
Yes. The grid scrolls sideways and everything is thumb-sized. On iPhone, turn off silent mode and tap play once, because iOS mutes web audio until you do.
Can I use what I make commercially?
Yes. The sounds are synthesised by code, not sampled, so there's no sample licence on your exports, and the notes you write are yours.
How do I save or share a loop?
It saves itself in your browser. Copy loop link packs everything into a URL that reopens it exactly, on any device.
Why can't I hear anything?
Tap play first (browsers block sound until you interact), check the part isn't muted, check the level slider, and on iPhone check the silent switch. It's always one of those four. Always.
Got a loop you love? Make it a full song.
The free Paddy Prompt Studio turns your loop's prompt into a polished Suno style, helps you format lyrics, and writes the matching Vidmuse music-video script.
Open the Prompt Studio →