Open-source, self-hosted platform to manage subscribers, run campaigns, and track analytics. Single Go binary with a Vue UI.

22.5k stars2.5k forksAGPL-3.0last commit Actively maintained

Cloud email delivery platform for sending marketing campaigns and transactional messages via SMTP and APIs. Offers a drag-and-drop email editor, templates, contact management, segmentation, automation workflows, deliverability tools, analytics, and third-party integrations.
Open-source, self-hosted platform to manage subscribers, run campaigns, and track analytics. Single Go binary with a Vue UI.

22.5k stars2.5k forksAGPL-3.0last commit Actively maintained
Postal is an open source mail delivery platform for sending and receiving email, with SMTP support, web-based management, and tools for running your own SendGrid-style service.

16.7k stars1.3k forksMITlast commit Actively maintained
Haraka is a fast, event-driven SMTP server for receiving, filtering, and relaying email, featuring a modular plugin architecture for customization at scale.

5.6k stars706 forksMITlast commit Actively maintained
Keila is an open-source newsletter tool for creating email campaigns, managing contacts and segments, building signup forms, and sending via SMTP or email providers.

2.2k stars161 forksAGPL-3.0last commit Actively maintained
Open-source emailing platform for newsletters and transactional emails with a visual MJML builder, segmentation, A/B testing, analytics, and a REST API with webhooks.

2k stars216 forkslast commit Actively maintained
AGPL-3.0 open-source email API for developers that can be self-hosted; supports SMTP sending, webhooks, DNS automation, observability, multi-tenancy, and project isolation.

708 stars37 forksAGPL-3.0last commit Actively maintained
A small, C-based Mail Transfer Agent for local submission and outbound relay with TLS/SMTP authentication, aimed at home and small office use.
262 stars59 forkslast commit Likely dormant
Lightweight SMTP server written in Go that receives and sends email via a single JSON config and executable hooks; supports per-user DKIM and TLS.

Activity unknown
Postfix is a fast, secure, and easy-to-administer SMTP server for sending and routing email on Unix-like systems, commonly used as an MTA or mail relay.

Activity unknown
E-MailRelay is a lightweight SMTP relay/store-and-forward mail server with optional POP3 access to spooled messages, designed for simple, scriptable mail handling.

Activity unknown
chasquid is a minimalist SMTP server (MTA) for individuals and small groups, focused on secure defaults, easy configuration, and straightforward operation.

Activity unknown
Exim is an open source SMTP message transfer agent (MTA) for Unix-like systems, offering flexible mail routing and extensive controls for handling inbound email.

Activity unknown
OpenSMTPD is an open-source, minimal SMTP daemon from the OpenBSD project providing an RFC-compliant MTA with privilege separation, table backends, filters and TLS support.

Activity unknown
Open Source Sendmail provides a subset of Proofpoint's Sendmail Sentrion MTA for large-scale mail deployments; current release is 8.16.1 with a PGP-signed tarball and OpenDKIM integration.

Activity unknown
Every option on this page is open source and free to run on your own hardware, so you own the data and there is no subscription to cancel. 6 of 14 shipped a commit in the last six months. Licences in this list: AGPL-3.0, MIT. In exchange you take on hosting, backups and updates yourself.
Browse everything in Email Servers (SMTP/IMAP).