Among open-source Mailchimp alternatives, Keila has the most modern UI - built in Germany on Elixir and Phoenix (the PETAL stack), with GDPR-conscious defaults including an optional no-tracking mode, and 100% open source with no proprietary premium tier. Campaign authoring is flexible three ways: a visual block editor with multi-column layouts, Markdown with or without WYSIWYG for hybrid HTML-plus-plain- text sends, and raw MJML for hand-coded designs. The personalization system is unusually clean - every contact carries custom data as a single JSON object (populated from sign-up form fields or pushed from your CMS/CRM), and Shopify's Liquid template language renders it into fully dynamic emails. Targeting uses a visual segment editor backed by a powerful segment language for complex logic over tags, language preferences, and any custom field. Sign-up forms with custom fields grow your lists; open and click tracking measures campaigns; scheduled sending handles timing. Delivery pipes through your own SMTP or first-class integrations with AWS SES (including automated bounce handling), SendGrid, Mailgun, and Postmark. A full REST API manages contacts, campaigns, and segments, with Erlang/OTP reliability underneath. Comfortable at 100K+ subscribers. AGPL-licensed, EU-hosted project, actively developed.

Keep your newsletter audience on infrastructure you own with LetterSpace, a self-hosted platform for subscriber lists, campaigns, and email analytics. Organize subscribers into lists inside your organization, enrich each address with metadata pairs, and use those values as placeholders inside the mail you send. Campaigns begin as drafts where subject, content, template, target lists, and tracking choices stay editable until you deliberately start the send. A test copy goes to your own inbox first, and a future schedule time holds the campaign until the moment arrives. Reusable HTML templates wrap every campaign in your house style, with the content injected at send time and an unsubscribe link in the footer. Once mail flows, the dashboard follows subscriber growth across six months, recent campaign delivery rates, and open and click performance compared between the last thirty days and the period before. Delivery itself runs through your SMTP settings with per-organization rate limits, retries, and concurrency controls, and provider webhooks can report bounces and confirmations back into message statuses. Signup forms and external tools connect through a REST API guarded by keys, with double opt-in available for new subscribers. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. MIT licensed.