Keila
Open Source Newsletter Tool
...Keila supports using a personal SMTP inbox for small-scale newsletters or integrating with major transactional email providers—AWS SES, Sendgrid, Mailgun, Postmark—for larger deployments. It offers a sleek WYSIWYG editor for campaign creation, version 0.17 adding features like mobile/desktop preview, preview emails, French localization, API enhancements, external contact IDs, and update notifications. Distributed under GNU AGPL‑3.0, and deployable via Docker or self-hosted using Elixir/Phoenix stack.