Gmail vs Mailtrain: What are the differences?
Gmail: A free web-based e-mail service. An easy to use email app that saves you time and keeps your messages safe. Get your messages instantly via push notifications, read and respond online & offline, and find any message quickly; Mailtrain: Self-hosted open-source Mailchimp clone. Mailtrain is a self hosted newsletter application built on Node.js (v5+) and MySQL (v5.5+ or MariaDB).
Gmail and Mailtrain can be primarily classified as "Email Marketing" tools.
Mailtrain is an open source tool with 4.01K GitHub stars and 435 GitHub forks. Here's a link to Mailtrain's open source repository on GitHub.