Dittofeed - open-source, omni-channel customer engagement platform
-
https://docs.dittofeed.com/deployment/self-hosted
From their Intro:
Dittofeed is an open-source, omni-channel customer engagement platform for automating messages to customers via email, SMS, webhooks, and native mobile push notifications. Automatically send templated onboarding messages, cart abandonment reminders, product updates and more with event-based triggers and branching logic. Dittofeed can be used to send both marketing and transactional messages.