Novu : The open-source notifications infrastructure. A fully-featured microservice to send SMS, E-mail, Slack and Push notifications. Embeddable notification...
SimpleLogin : With email aliases , you can be anonymous online and protect your inbox against spams and phishing. Open-source.
Matrix : Matrix is an open standard for decentralised communication, providing simple HTTP APIs and open source reference implementations for securely distribu...
Appwrite : Appwrite is an end-to-end backend server for Web, Mobile, Native, or Backend apps packaged as a set of Docker microservices. Appwrite abstracts the co...
Mailtrain : Mailtrain is a self hosted newsletter application built on Node.js (v5+) and MySQL (v5.5+ or MariaDB). Mailtrain supports subscriber list management, ...
Postal is a complete and fully featured mail server for use by websites & web servers. Think Sendgrid, Mailgun or Postmark but open source and ready for you to run on your own servers.