Open-Source Alternatives to SendGrid

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

This project is a Node.js email templating engine and SMTP delivery framework used for creating, rendering, and sending custom email templates. It provides a comprehensive suite for email orchestration, including a system for dispatching templated messages and a tool for generating custom layouts to standardize outbound messaging. The framework includes a dedicated HTML CSS inliner that converts external stylesheets into inline styles for consistent rendering across different email clients. It also features a multilingual localization tool for translating template text and subject lines, and

Postal is an open-source mail delivery platform designed for self-hosted sending and receiving of email using standard mail transfer protocols. It serves as a comprehensive email infrastructure that provides full delivery tracking and management of outgoing mail streams. The system includes an SMTP server manager with a web administration interface for configuring server settings and monitoring delivery status. It distinguishes its outbound traffic management through priority-based IP rotation and assignment to help maintain sender reputation. The platform covers incoming email processing an

Postal is an open-source email infrastructure and self-hosted delivery platform. It functions as an SMTP mail server and inbound email gateway, providing the tools necessary to send and receive email through a privately managed infrastructure. The system manages SMTP infrastructure for outgoing message delivery and provides capabilities for custom email receiving. It allows for the routing of incoming external emails to internal applications or websites for automated processing. The platform includes support for multi-tenant domain mapping, event-driven webhook notifications, and plugin-base

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

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

Mox is a self-hosted email server that runs as a single compiled Go binary, handling the full lifecycle of sending and receiving email through SMTP, IMAP4rev2, and a built-in webmail application. It is designed to be operated without external dependencies or runtime plugins, with all mail services — including spam filtering, queue management, and web interfaces for administration and account management — contained in one executable. The server distinguishes itself through automated TLS certificate management via ACME, DNS-based autoconfiguration for email clients, and file-based configuration

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

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