Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
PayPal - PayPal is the faster, safer way to pay online without sharing financial details, send and receive money or accept credit and debit cards as a seller
Geary - Geary is an email application built for GNOME 3.
Payoneer - Whether making international payments, receiving funds, managing your digital business, or accessing capital, Payoneer opens your business up to the world.
The Bat - The Bat! is a secure desktop email client for Windows, designed to protect your correspondence against third-parties and to save your time.
Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.