Open-Source Alternatives to Klaviyo

Plunk is an SMTP email marketing platform and contact relationship manager used for sending bulk broadcasts and transactional emails. It provides a transactional email API for delivering personalized messages using templates and variable substitution, supported by built-in analytics and custom domain authentication. The platform features an email automation workflow engine with a visual builder for creating multi-step sequences triggered by user events and conditional logic. It includes a dynamic audience segmentation tool that groups contacts based on real-time data attributes and behavioral

Listmonk is a self-hosted email marketing platform and newsletter manager designed for high-volume bulk email distribution and transactional messaging. It provides a centralized system for organizing large subscriber databases and executing automated marketing campaigns directly from your own infrastructure. The platform distinguishes itself through its reliance on a relational database backend, which enables dynamic subscriber segmentation using complex query filtering at the time of delivery. It utilizes a concurrent worker pool to manage high-throughput email dispatch and incorporates a se

Mautic is an open-source marketing automation platform and self-hosted CRM built with PHP. It functions as an audience manager and marketing suite designed for automating lead nurturing, designing customer journeys, and managing multi-channel campaigns on private infrastructure. The system distinguishes itself through a visual workflow engine and campaign builder that model customer journeys via conditional nodes. It incorporates a behavioral tracking engine to monitor website visitor activity, which informs lead engagement scoring to prioritize high-value prospects. The platform covers omni

Mailtrain is a self-hosted newsletter platform and email marketing tool designed for managing subscriber lists and sending automated email campaigns from a private server. It provides a centralized system for coordinating the creation and delivery of recurring email outreach. The platform includes a visual email template builder for creating responsive layouts and a subscriber management system that uses custom fields to organize audiences into targeted segments. Automation is handled through tools that can trigger newsletters based on remote feeds and scheduled events. Performance is tracke

Mail for Good is a bulk email marketing platform designed for managing subscriber databases, designing templates, and executing high-volume outreach campaigns. It functions as an email list management tool that facilitates contact data imports and the capture of new leads. The platform features an analytics dashboard for monitoring delivery metrics, tracking bounce rates, and measuring recipient engagement. It includes a role-based access control system to manage user permissions and secure the coordination of shared marketing accounts and campaigns. The system covers a broad range of capabi

useSend is an email marketing platform and transactional delivery system built to manage bulk campaigns and individual messages using AWS SES for delivery. It provides a RESTful API, an SMTP relay gateway, and a visual management interface for designing HTML templates and coordinating email broadcasts. The platform distinguishes itself by translating legacy SMTP traffic into modern API calls and implementing an event-driven webhook system. This system pushes real-time delivery, bounce, and click notifications to external servers using HMAC-SHA256 signed payloads to ensure authenticity. The s

Dittofeed is an open-source customer engagement platform designed to orchestrate personalized multi-channel messaging journeys. It functions as a marketing automation system that segments user audiences based on behavioral and attribute data, triggering automated communication sequences across email, SMS, and mobile push channels. The platform distinguishes itself through a self-hosted architecture that allows organizations to maintain full control over sensitive customer data within private networks. It treats marketing assets and journey logic as version-controlled entities, enabling collab

BillionMail is a self-hosted email infrastructure and marketing platform designed to provide full control over mail delivery, domain management, and subscriber communication. It functions as a comprehensive mail server manager that enables users to deploy and maintain private email environments, including integrated webmail interfaces for direct account access. The platform distinguishes itself by combining high-volume bulk email distribution with sophisticated deliverability tools. It supports multi-tenant infrastructure provisioning, allowing administrators to manage multiple domains and ma

EspoCRM is an open-source customer relationship management platform and SQL-based business application. It serves as a centralized web interface for tracking leads, opportunities, and contacts, providing a sales pipeline manager and a customizable business logic engine. The platform is distinguished by its ability to function as a custom business application builder, allowing for the creation of tailored entities and automated workflows. It integrates marketing automation tools for campaign coordination and a structured customer support ticketing system for case management. The system covers

SuperAGI is a comprehensive marketing automation platform and customer data system designed to orchestrate multi-channel engagement workflows. It functions as a no-code workflow orchestrator, allowing users to build complex, automated task sequences triggered by real-time user behavior, transactional data, or scheduled events. By centralizing customer profiles and interaction history, the platform enables businesses to manage end-to-end marketing operations from a single interface. The platform distinguishes itself through its deep integration with e-commerce storefronts and its ability to ex

Monica is a self-hosted personal relationship manager and CRM designed to track personal and professional connections. It functions as a contact management system and personal information manager, providing a centralized repository for detailed contact profiles, interaction logs, and relationship history. The system distinguishes itself by focusing on the nuances of personal connections, including gift cataloging, debt tracking, and personal journaling. It features a time-triggered notification system for scheduling contact reminders, such as birthdays and follow-up intervals. Broad capabili

This project is a reference implementation of a production-ready backend API built with Rust and the Actix-Web framework. It serves as a codebase demonstrating the development of a newsletter subscription service, encompassing the management of subscriber sign-ups, email confirmations, and campaign delivery. The project highlights a layered architecture that separates concerns into handler, service, and repository layers. It utilizes an actor-based concurrency model for handling HTTP requests and employs trait-based abstractions to decouple business logic from external dependencies, such as e