cal.com : Open source meeting scheduling tool. Send a link, let others book a slot. Calendly alternative.
Maily Herald : Maily Herald is a Ruby on Rails engine that helps you send and manage your mailings.
Think of Maily as a self-hosted Mailchimp® you can easily integra...
Novu : The open-source notifications infrastructure. A fully-featured microservice to send SMS, E-mail, Slack and Push notifications. Embeddable notification...
Mailtrain : Mailtrain is a self hosted newsletter application built on Node.js (v5+) and MySQL (v5.5+ or MariaDB). Mailtrain supports subscriber list management, ...
A set of Ansible playbooks to build and maintain your own private cloud: email, calendar, contacts, file sync, IRC bouncer, VPN, and more.