Osu (acquired by PayPal)

Osu was a powerful payments, scheduling, and business management app for sole traders, the self-employed, and small businesses. Using the Osu app, thousands of small businesses were able to accept payments with zero transaction fees and instant settlement, seamlessly manage their customers, control their schedule and accept more bookings, issue professional invoices, easily scan receipts and track expenses, automate late payer chasing, and much more.