Telepat.io Cloud - Open source, real time API platform
MailtoUI.js - Enhance your mailto links with a convenient user interface.
Mashape API Platform - Distribute, Monetize, Manage and Consume APIs
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.
Emburse Expense Card API - The first card API platform with app integrations
The Simple Postcard - Text a photo to mail it as a postcard