Main Street Hub - Omni-channel marketing platform for local businesses.
Lob - A simple API to integrate print & mail solutions into your applications.
Enthusem - Enthusem offers personalized direct mail marketing solutions.
PostGrid - Transform your Offline Communications. Use our fully-documented REST API to send personalized letters, checks, postcards and improve address accuracy.
AmazingMail - Business print-mail solution
Docsmit Mail - Send USPS Certified, Priority and First Class mail from Windows, Word or Web. API too.