Best Self-hosted Communication & Collaboration tools in 2026
168 self-hosted open source alternatives in this category
168 services found
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.
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 Ope...
Stackspin
Open source collaboration suite with SSO and admin dashboard
Stackspin is an open source platform that bundles common team collaboration apps with single sign-on, centralized user management, backups, and monitoring for admins.
Zimbra Collaboration
Enterprise email, calendar, contacts, and collaboration suite
Self-hosted enterprise collaboration suite providing email, webmail, calendaring, contacts, and administration for organizations.
Citadel
Groupware server with email, calendaring, contacts, and web access
Citadel is an open source groupware and messaging server providing email, calendars, contacts, and a web interface with room-based collaboration.
WikiSuite
Integrated suite for knowledge management, collaboration, and IT admin
WikiSuite is an integrated open source suite combining wiki/groupware, chat and conferencing, webmail, search, and infrastructure management for organizations.
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.
SIP3
SIP and VoIP QoS monitoring with call flow analytics
Self-hosted platform for capturing SIP/RTP traffic, analyzing call flows, and monitoring VoIP quality metrics with dashboards and alerts.
Courier Mail Server (Courier MTA)
Integrated mail server suite with SMTP, IMAP, POP3 and webmail
Courier is an integrated mail server suite providing ESMTP (MTA), IMAP, POP3, webmail, and mailing lists with optional LDAP/MySQL/PostgreSQL-backed virtual accounts.
Jami
Distributed, open source communication platform for calls and messaging
Jami is a distributed communication platform for private messaging, audio/video calls, and conferencing, designed to work without central servers and with end-to-end encr...
Libervia
Multi-interface XMPP client and social platform
Libervia is a modular XMPP-based communication suite offering chat, microblogging, file sharing, and other social features across web, desktop, and CLI interfaces.
SquirrelMail
Browser-based IMAP webmail client written in PHP
Lightweight PHP webmail client for IMAP/SMTP servers, offering a simple interface, plugin extensibility, and broad compatibility with standard mail backends.
DAViCal
CalDAV server for shared calendars and scheduling
DAViCal is an open source CalDAV/WebDAV calendar server using PostgreSQL, enabling shared calendars, access delegation, and meeting scheduling across many clients.
u-wave
Self-hosted collaborative music listening with a shared queue
u-wave is a self-hosted social music room with DJ-style queueing, chat, and browser-based playback for listening together in real time.
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.
Dovel
Simple Go-based SMTP server for receiving and sending mail
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.
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.
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.