Listmonk

Listmonk is a free and open-source self-hosted newsletter and mailing list manager that allows users to manage one-way mailing lists with millions of subscribers. It is designed for high performance, packed into a single binary that runs on various operating systems.

1. Self-Hosted: Full control over your data and environment.
2. Performance: Capable of handling campaigns with over 7 million emails.
3. One-way Mailing Lists: Manage single and double opt-in lists with custom attributes.
4. Bulk Importer: Fast importing of subscribers (up to 10k records/sec).
5. Transactional Mails: API for sending SMS, WhatsApp messages, and emails.
6. Analytics: Visualizations and easy database connection for external tools.
7. Templating: Dynamic email templates using Go templating language.
8. Media Management: Upload and manage images for campaigns.
9. Extensible: Connect webhooks for various messaging services.
10. Privacy Features: Allow subscribers to manage their data and blocklist themselves.