Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.

haptik - The first always-on metronome for Apple Watch

music21 - Music21 is a Python-based toolkit for computer-aided musicology.

YesNoWTF Messenger bot - GIF backed foolproof™ decision making Messenger bot

DaCapo Editor - DaCapo Editor is a free Open Source music sheet editor which allows to easily create nice looking partitions. It is available as a web application as well as a desktop application for Windows, MacOS and Linux.

Versus for iMessage - Let friends help you make the best decisions