Lob - A simple API to integrate print & mail solutions into your applications.
PostGrid - Transform your Offline Communications. Use our fully-documented REST API to send personalized letters, checks, postcards and improve address accuracy.
Click2Mail - Mail outsourcing on-demand.
AmazingMail - Business print-mail solution
Sendoso - Sendoso’s B2B engagement platform helps companies accelerate sales and retain customers with gifts and rewards.
Growmail Automated Direct Mail - Growmail enables businesses to send letters and postcards instantly through Automated Direct Mail.