https://www.gmass.co/features/gmail-transactional-emails
GMass's transactional email SMTP service: Send better transactional emails through your Gmail...
Mar 22, 2022 - With the GMass SMTP service, you can send transactional emails through your Gmail account for better reliability, searchability and more.
transactional emailgmasssmtp
https://www.validity.com/litmus/
Litmus from Validity: Everything you need to send better emails.
Nov 26, 2025 - Litmus from Validity brings your entire email workflow—from design and building to boosting deliverability—into one user-friendly platform.
send better emailslitmusneed