Piano - Piano lets you quickly learn the piano or other musical instruments using cell phones and tablets, and also contains magic tiles and different mini-games.

Flowkey - The easiest way to learn piano with your iPhone or iPad

Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.

Yousician - Learn to play music at home, at your own pace

Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.

Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.