source code @ https://github.com/jakeonaut/neocomposer

How to Play:

Click (and drag) the grid to place notes!
Quickly click a note again to delete it!
Press Space to play / pause!
Use asdfghjkl; and wetyuop keys to practice!
- Plus and minus keys increase or decrease the octave.
Use 1, 2, 3, etc. to quickly swap between instruments!
Ctrl+Z and Ctrl+Y kind of work too!

Expert Tips:

Use shift to quickly swap between note pencil and select mode!
Hold shift + drag the cursor to select notes!
Press shift + 1, 2, 3, etc. to select all notes for a given instrument!
Use escape to clear note selection!

I made a little midi sequencer for your browser! 
Inspired by Mario Paint Composer and other similar tools, 
I wanted something that could import soundfont files and make silly little tunes.
There's still some stuff I want to fix 
but feel free to use it to your hearts content!

TODO (ignore if ur not jakeonaut):

[ ] handle save/load with different .sf2s then the default !

[ ] undo is saved weird when clicking and dragging notes (saves a weird in-between state)
[ ] this is similar but even worse with moving with arrow keys,
[ ] undo / redo when deleting an instrument ? (or creating an instrument?)
will have to have a max undo history though probably..
[ ] moving notes with arrow keys should only save an undo state after the user changes (or removes) selection
[ ] - :think: patterns???? (https://github.com/danigb/smplr#pattern-chain-song-mode)

[ ] make it play nicer in mobile
[ ] Longer tracks
[ ] QOL - should we delete notes that were dragged off the left of the playhead? (when selected with an offset)
[ ] QOL - could remove notes from the selection that are reselected with shift (like a toggle... like Finder)
clicking and dragging multiple triplet notes doesn't properly set their relative note offsets to each other
same with clicking and dragging quarter notes when triplets are ALSO selected

More information

Updated	2 days ago
Published	11 days ago
Status	Released
Category	Tool
Platforms	HTML5
Rating	Rated 4.8 out of 5 stars (6 total ratings)
Author	petsclub2
Tags	browser, composer, daw, mario-paint, Music, Music Production, tool
Content	No generative AI was used