One-way mailing lists
Manage millions of subscribers across single and double opt-in lists. Query and segment subscribers with SQL expressions.
Analytics
Built-in analytics to visualize campaign performance, bounces, top links and more across campaigns.
Templating
Create powerful, dynamic e-mail templates with the Go templating language. Use template expressions, logic, and 100+ functions in subject lines and content. Write HTML e-mails using a visual drag-and-drop builder, a WYSIWYG editor, Markdown, raw syntax-highlighted HTML, or just plain text.
Performance
Multi-threaded, high-throughput, multi-SMTP e-mail queues. Throughput and sliding window rate limiting for fine grained control. Single binary application with nominal CPU and memory footprint that runs everywhere.
CPU usage is a fraction of a single core with peak RAM usage of 57 MB.
Transactional mails
Simple API to send arbitrary transactional messages to subscribers using pre-defined templates. Send messages as e-mail, SMS, Whatsapp messages or any medium via Messenger interfaces.
Extensible
More than just e-mail campaigns. Messenger HTTP webhooks to send SMS, Whatsapp, FCM notifications, or any type of messages. Extensive API coverage for all features.
And a lot more ...
Full privacy control for subscribers, OIDC SSO authentication with granular roles and permissions, granular API tokens, media library with S3-compatible backend and a lot more.