PETAPORON is a minimalistic piano roll sequencer.
Compose a song and export it to mp3!


  • space: start/stop playback
  • left arrow: navigate one bar forward
  • right: navigate one bar back
  • alt+left: go to the start of the song
  • backspace / delete: delete selection
  • cmd+z: undo
  • shift+cmd+z: redo 
  • cmd+x: cut selection
  • cmd+c: copy selection
  • cmd+v: paste
  • cmd+s: save song data to a text file (to reload it: drag&drop this file on Petaporon)
  • cmd+e: export song to mp3
  • cmd+n: new song

10 instruments sets available !

01MARIO PAINT(Mario Paint, SNES)
04CHRONO(Chrono Trigger, SNES)
05ZELDA(Zelda: A link to the past, SNES)
06YOSHI(Yoshi Island, SNES)
07ANIMAL(Animal Crossing, Nintendo DS)
08STARFOX(Starfox, SNES)

More instruments will be added in future releases.
Follow our development logs!

Development log


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Viewing most recent comments 1 to 40 of 48 · Next page · Last page

This is fantastic! I absolutely love it. I do wish there was an executable version with fullscreen for easy of use, but it really is great.


i think all this needs is to have a fullscreen option. mighty fine tool though!

And when you make it a Linux-available executable (as suggested by Teafan), will you reveal the format the instrument sets are in?

I'd love to import some others.
(MOTHER 3 has the most realistic sax, trumpet, and electric guitar I have ever heard in a 16-bit game)

this might easily be my favorite easy song maker out there 

incredibly versatile, easy to pick up and use, customizability off the charts, just got everything completely right

if you plan on making this into an executable that would be great! it would be a pretty useful tool

also could you maybe make it so that you can export your song as a midi?


Are You ever planning to make this an Executable and release it on Linux? 

I'd love to use this tool offline

i have been serching for over 5 months for the a easy to learn music program to make music for my game, thank you so much for making this

The play button or pressing space doesn't seem to work in firefox /: other than that it's a cool tool

This is so amazing!

Are you planning to port it to other platform like desktop or mobile app?

mate this is the coolest online editor ever , it would be pog if there was a desktop download version :D

and the UI oh my gosh so satisfying 🤩


this is so awesome ! thx alot 


could you add cmd+a to select all?



The solution of FamiStudi

Very very cool! Thanks for this fun little tool.

Just a little "problem", when you export in Mp3, the rhythm is changed, I guess it's already a known problem, but just in case ^^.

But otherwise, it's really fun!

Well done!

yes, i think it gets a bit slow, but it's really a good tool. 👍

pls try update only that

and maybe, you can add drums other than the 2 drum box.

It’s quite a fun and nostalgic little piano roll.

everything is great but how do you load in a song if you wanna work on it more?


Simply drag and drop the song file onto Petaporon UI to load it.

is anyone else noticing a difference in quality when you export an MP3?

yeah the song seems to slow down sometimes

I really love the look of the UI!

Yeah this is so cool also hi frand!

Ahhh, hello! :D


I can't figure out what the groove buttons do, please help

it seems the farther you go to the right, it turns up the amount of "swing" 

Swing—sometimes called Groove or Shuffle—is the addition of tiny delays to every other hit of a beat.


is there any way for me to download this for offline use? I love it!

(1 edit) (+3)

Yes, using the itchio desktop client

I just keep coming back to play with this!

I have a couple of ideas:

The Super Mario Sunshine acapella soundfont and the Minecraft soundtrack instruments would make great instrument packs to play around with.

Fullscreen option?
Maybe also the ability to increase/decrease the octaves
on the piano with +/- buttons?

I am a dev with some background in music -
would love to talk more about this with you.

Everything you've done up to this point is solid, thanks for putting it online!

Doesn't work on Microsoft Chromium Edge. Seems like a great tool, bookmarked in hopes the bugs are ironed out.

(1 edit)

Really obssessed with this... fantastic job!

One thing I wish it could do is change selected notes to a different instrument.

I don't think I have the low pitch issue when exporting to .mp3, but it sure sounds in slower bpm although maybe it's my fault, I don't know much about music stuff... I was wondering about the g r o o v e buttons as well (I made sure the bpm/speed gauge was at the center when exporting)

I've uploaded the .json and the .mp3 to google drive in case it helps

Anyways, GREAT tool though, makes composing easy and especially refreshing for noobs like me!

Wow, good!

This is a really nice sequencer. It really deserves a bit of work to fit a phone screen so we could compose on the go 😉


Nice tool! It would be cool if pressing up/down arrows the selected notes shift by an half step and another shortcut (ctrl or Alt + up/down arrow? I don't know) to shift the selected notes by an octave, last thing, maybe the black keys should have a slightly darker row, so everything is more readble . However these are only suggestions, you already did a great job!


are any of these instrument sets available as soundfonts? the kantan one is amazing


I love using this tool and the new instruments sets are cool but something I find annoying is when I export the music the pitch is off and I have to go into audacity to fix the pitch.

(2 edits) (+1)

Thanks for the report. What I think is happening is that the sample rate initialize to something different than 44.1KHz, and this messes with some parts of the sound engine or the renderer. It’s quite difficult for me to debug, as I can’t reproduce this issue on my machines.

Is the tempo also different when you export, or only the pitch is affected?

By any chance, would you be able to share both the exported .json and .mp3 files of a track you made, so I can have a look?

(1 edit) (+2)

I made an itch page with the mp3 and json


Thanks a lot, this is helpful


Hi PepperBoi,

I made an attempt to fix the exporter pitch issue. Can you try again, and tell me if that fixed it for you?


It seems to be fixed!


Nice! Thanks for the help.

Great tool, but can you add a tempo visualizer?

copypasting doesn't work?


copy/paste should work: select a group of notes with right-click and dragging the selection rectangle around the notes to copy (note are highlighted in white). Then ctrl-C, ctrl-V, and finally move the copied notes to another position.

If it still doesn’t work, can you describe what you are doing and what is happening?

when I move the notes, there are no copies left behind. Ctrl-c Ctrl-v doesn't work for some reason, as do ctrl-z etc. , and the cmd-c, cmd-v, cmd-z etc. don't work either!


I’m not sure to know what is the problem, but it might be caused by a conflict with the browser’s own shortcuts handlers. Just by curiosity, can you tell me which web browser you are using?

To try to fix that, I added a new option in the settings menu to allow using shortcuts without pressing ctrl/cmd keys. ctrl+Z just become Z, and so on.

You need to refresh the page after changing the option for it to take effect.

still doesn't work, and i'm using Firefox


I tested on Firefox and I had the same issue as you. But the new option fixed the problem for me.

Please make sure you checked the “do not require ctrl/cmd” radio button in the Petaporon’s settings (top-left corner button). Then reload the page (make sure the option is still set after reloading. Petaporon store the settings in the browser’s local storage).

Only press Z to cancel (ctrl+Z will probably still conflict with Firefox, so Petaporon will not receive the keystroke). Similarly, only press X, C and V to cut, copy and paste selection of notes.

For some reason it seems to export all songs at a lower key and tempo?? Is there a fix for this?

Great program btw, very fun to use!



it’s probably an issue related to the sample rate of the sound card that is not 44.1kHz (what Petaporon is assuming). I had a similar problem in another project. I’ll try to have a look.

I tried to make a fix, but I cannot test it because this bug doesn’t happen on my machine.

If you have some time, could you please test and tell me if the problem is still happening?

(1 edit)

Sorry, I just saw your reply.
Now I can't even seem to export it. It gets stuck on the loading bar of it "encoding". Very strange...
Hopefully it works for other people though, and judging by the comments I think it is???

Sorry I can't be of more help! Thank you for trying to fix it.

Oh my god, now will I not need to get things like fl studio or reaper to make music for my game! I really like the chiptune group thingie. Love it <3


I know everybody asks this, but why you don't make a downloadable version of this?



It has been asked several times. But the reality is that it’s a lot more work to manage and distribute executables, when compared to a web version.

For this project, I just want to keep things simple for now.


Love the Asprite style


Did you reply to your own post? That’s happening a lot recently.

I am so dumb XD

you have the software in .exe file ? i want run it offline c:

I don't think so.

That might be possible in the future, but for now, you'll need the itch app to use this offline.


I love this tool! Will be using it for game jams and prototyping tunes. One thing though, I can’t work out how to copy and paste a block of notes, is that possible?

Thanks -Chris

Ignore me, figured it out after posting, doh!


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