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.

ChordU - Extracts chords from any song, integrated YouTube.

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.

Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.

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

yalp.io - Automatic chords extraction from mp3 and YouTube