mail-tester.com : Free online service that allows you to test your emails for Spam, Malformed Content and Mail Server Configuration problems
SimpleLogin : With email aliases , you can be anonymous online and protect your inbox against spams and phishing. Open-source.
Email Standards Project : The Email Standards Project is about working with email client developers and the design community to improve web standards support and accessibility ...
Novu : The open-source notifications infrastructure. A fully-featured microservice to send SMS, E-mail, Slack and Push notifications. Embeddable notification...
Dada Mail : Dada Mail is a Contemporary Mailing List Manager, enabling you to easily run a verified mailing list that your subscribers can trust, right on your ow...
Firefox addon to simplify the use of temporary e-mail addresses in order to protect your real address from spam.