Notif.me SDK - A Node.js lib to send all your transactional notifications
Cryptominded - Where you learn more about cryptocurrencies
Clank - Explore the biggest crypto transactions across blockchains
Crypto Buyer's Guide - Extensive cryptocurrency buying guide
Pusher - Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.
Robinhood - Free stock trading service.