Ghost
Publishing platforms for blogs, websites and newsletters.
Open Source Alternatives to Keila
Reliable and easy email newsletters
listmonk
Newsletter and mailing list manager
About Keila
Keila is open source and also offers a hosted service. It focuses on data-driven newsletter campaigns and managing contact lists.
The Product
Keila supports Live Statistics for opening rates, click rates, and more. Their newsletter builder supports HTML and Markdown. Newsletter can be distributed through SMTP, AWS SES; Mailgun, Postmark and Sendgrid. It supports Double-Opt in and hCaptcha in its custom signup forms.