Cash App - The easy way to send, spend, bank, and invest.
Typora - A minimal Markdown reading & writing app.
Facebook Pay - Send money to your friends via Messenger
Dillinger - joemccann has 95 repositories available. Follow their code on GitHub.
PayPal.Me - Request money using your own personalized URL.
StackEdit - Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.