Best Self-hosted Email Servers (SMTP/IMAP) tools in 2026
44 self-hosted open source alternatives in this category
See also:
Calendars & Contacts (CalDAV/CardDAV)Collaborative Office SuitesTeam Chat & MessagingVideo Conferencing & WebRTCVoIP / SIP & PBXWebmail Clients44 services found
E-MailRelay
Lightweight SMTP store-and-forward MTA with optional POP3 access
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.
Exim
Configurable SMTP message transfer agent for Unix-like systems
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.
GNU Mailman
Mailing list management and e-newsletter distribution software
GNU Mailman is a mailing list manager for email discussion lists and newsletters, with web-based administration, archives, moderation tools, and bounce handling.
HyperKitty
Web archiver and user interface for Mailman 3 mailing lists
HyperKitty is a web interface and archiver for Mailman 3 mailing lists, providing searchable list archives, thread views, user profiles, and email interaction features.
Inboxen
Disposable email inbox service with unlimited unique addresses
Inboxen provides unlimited unique email inboxes to protect your primary address from spam, sign-ups, and tracking while keeping your real inbox clean.
OpenSMTPD
Secure, lightweight SMTP server implementation compliant with RFC 5321
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.
Postfix
Secure and efficient SMTP mail transfer agent (MTA)
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.
Postorius
Django-based web interface for GNU Mailman 3 mailing lists
Postorius is a Django web UI for managing GNU Mailman 3 mailing lists, covering list administration and user subscription preferences.
Schleuder
OpenPGP-enabled mailing list manager with remailing
Schleuder is an OpenPGP-enabled mailing list manager that encrypts list mail and supports remailing, allowing subscribers and non-subscribers to exchange secure emails via the list.
Sendmail Open Source
Open source subset of Sendmail Sentrion for enterprise email environments.
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.
Simple NixOS Mailserver
NixOS module for running a complete email server stack
Simple NixOS Mailserver provides NixOS modules to deploy a full email server with SMTP/IMAP, spam filtering, DKIM/DMARC/SPF, and TLS automation.
Zimbra Collaboration
Enterprise email, calendar, contacts, and collaboration suite
Self-hosted enterprise collaboration suite providing email, webmail, calendaring, contacts, and administration for organizations.
b1gMail
Web-based email and collaboration suite for running hosted email services
Open-source webmail and groupware offering email, contacts, calendar, cloud drive, tasks, notes and an admin control panel for multi-tenant email services.
chasquid
Simple and secure SMTP mail transfer agent (MTA)
chasquid is a minimalist SMTP server (MTA) for individuals and small groups, focused on secure defaults, easy configuration, and straightforward operation.