Blockbutler - Real-time transaction notifications for the blockchain
Mailjoy - Delightfully easy direct mail marketing. A DIY direct mail tool created for marketing and growth teams. Design, mail & track personalized direct mail postcards and letters. Digital marketers use Mailjoy to send data-driven mail campaigns.
Notif.me SDK - A Node.js lib to send all your transactional notifications
Felt for iPhone - Handwritten cards for the modern world
Pusher - Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.
Handwrytten - Handwritten notes straight from your device. Huge selection of cards or design your own. Handwriting service integrates with 1000's of apps.