MuseScore thrives on developer contributions in the form of both contributed code and patches. Helping out in development helps the project move forward and stay competitive, and it is the best way to ensure that MuseScore can do what you need it to do on your next musical project!
Hosted on GitHub: MuseScore's source code and development hub (commits feed / RSS). The preferred way to contribute is via pull request (currently open PRs). Read our Git Workflow page to learn how to make a pull request. You need to sign the MuseScore CLA for your request to be merged.
Devs use GitHub Wiki and Developers' handbook: information including build/compile instructions for supported OSes.
Group chat on Discord.com
Development and Technology Preview forum
Mobile apps (Android, iOS) and the MuseScore.org and MuseScore.com website
Read How and where to ask for support to understand the Muse Group ownerships and MuseScore's open source model (wikipedia) first. Mobile apps (Android, iOS) and all of MuseScore's websites are closed source so direct code contribution is not possible.
Help us with musescore.org documentation (Handbook, Tutorials and How to), which depents on online community. Use forums to propose improvements of the musescore .org.
Visit MuseScore.com groups to propose improvements of musescore .com website, Android app and iOS app.
Visit https://musehub.zendesk.com/ to propose improvements of Muse Hub.
Developers' Handbook Plugin Chapter
Plugin forum: help others write plugin, you don't even need to open MuseScore.
MuseScore 3.x compatible soundfont, instruments and MIDI CC
Developers' Handbook Soundfont, MIDI velocity and instruments.xml
Other ways to contribute
Visit contribution overview to find out all you can do to help MuseScore grow, such as proposing new design, translating, testing and bug reporting etc.