Best Self-hosted Communication & Collaboration tools in 2026

A small, C-based Mail Transfer Agent for local submission and outbound relay with TLS/SMTP authentication, aimed at home and small office use.

Likely dormant

Alternative to:

Postfix+11

Create, share and combine structured tables and views inside Nextcloud. Supports templates, CSV/spreadsheet import, custom columns, filtered views and an OpenAPI-backed API.

AGPL-3.0Actively maintained

Alternative to:

Google Sheets+8

Community-focused server for private photo/video backup, albums, chat and audio/video calls with mobile app support and S3-compatible storage.

MITActively maintained

Alternative to:

Google Photos+10

An IRC network implementation in Go that uses the Raft consensus algorithm to eliminate netsplits and provide transparent client failover via a bridge.

BSD-3-ClauseActively maintained

Alternative to:

IRCCloud+3

Open-source, modular SIP server (proxy, presence, conference, B2BUA) with push gateway, ICE/STUN/TURN, MySQL/SQLite support; optimized for mobile and embedded systems.

AGPL-3.0Actively maintained

Alternative to:

3CX+11

Open-source event listing and aggregator built on Laravel. Provides iCal feeds, tags, RSVP, photos, and multiple authentication methods for community and organization event sites.

MITActively maintained

Alternative to:

Meetup+6

SAMA is a Node.js-based open-source chat server using uWebSockets.js, MongoDB and Redis, providing WebSocket/HTTP APIs, E2EE, clustering, and web/mobile clients.

GPL-3.0Actively maintained

Alternative to:

Sendbird+19

Atria is an AGPL-3.0 open-source platform for managing hybrid events, sessions, sponsors, and real-time attendee networking with chat and discovery tools.

AGPL-3.0Slowing down

Alternative to:

Whova+16

Integrated installer and platform for home infrastructure. Provides VPN relay for NAT traversal, preconfigured email, automatic HTTPS, reverse proxy, and a web management utility.

GPL-3.0Actively maintained

Alternative to:

Cloudron+19

Open-source PWA that generates live captions and transcripts in the browser; supports broadcasts, OBS/vMix integration, and optional Azure AI captions.

GPL-3.0Actively maintained

Alternative to:

Rev+6

Python-based Discord bot that lets authorized users list and control Docker containers and images via Discord commands, using the host Docker socket.

GPL-3.0Likely dormant

Alternative to:

Carl-bot

Open-source PHP groupware providing CalDAV/CardDAV, ActiveSync, email client, CRM, tasks, file manager and Docker images for on-premise collaboration.

AGPL-3.0Actively maintained

Alternative to:

Microsoft Exchange Online+19

Citadel is an open source groupware and messaging server providing email, calendars, contacts, and a web interface with room-based collaboration.

Activity unknown

Alternative to:

Microsoft Exchange Online+19

Collabora Online Development Edition (CODE) provides a self-hosted LibreOffice-based online editor for documents, spreadsheets and presentations for testing or small teams.

Activity unknown

Alternative to:

Collabora Online+13

A single-binary, low-resource Matrix homeserver in Rust; simple setup, RocksDB (default) or SQLite backends, built with axum and Ruma.

Activity unknown

Alternative to:

Element Matrix (Hosted)+19

Continuwuity is a fast, lightweight Matrix homeserver written in Rust, focused on stability, performance, and improved Matrix specification compliance for federation.

Activity unknown

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Element Matrix (Hosted)+6

Courier is an integrated mail server suite providing ESMTP (MTA), IMAP, POP3, webmail, and mailing lists with optional LDAP/MySQL/PostgreSQL-backed virtual accounts.

Activity unknown

Alternative to:

Microsoft Exchange Online+14

DAViCal is an open source CalDAV/WebDAV calendar server using PostgreSQL, enabling shared calendars, access delegation, and meeting scheduling across many clients.

Activity unknown

Alternative to:

Google Calendar+4

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

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Amazon Simple Email Service (Amazon SES)+11

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

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SMTP2GO+9

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

Alternative to:

Amazon Simple Email Service (Amazon SES)+10

Modular, PHP/JavaScript web GUI that configures and manages Asterisk PBX features, endpoints, and call routing for businesses and service providers.

Activity unknown

Alternative to:

3CX+11

GNU Mailman is a mailing list manager for email discussion lists and newsletters, with web-based administration, archives, moderation tools, and bounce handling.

Activity unknown

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Groups.io+4

A lightweight, curl-first free/busy scheduler that syncs availability from a CalDAV calendar and can send iCal booking invites via SMTP.

Activity unknown

Alternative to:

Calendly+11

HyperKitty is a web interface and archiver for Mailman 3 mailing lists, providing searchable list archives, thread views, user profiles, and email interaction features.

Activity unknown

Alternative to:

Cryoserver Email Archive

Inboxen provides unlimited unique email inboxes to protect your primary address from spam, sign-ups, and tracking while keeping your real inbox clean.

Activity unknown

Alternative to:

Mailinator+3

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 encryption.

Activity unknown

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Signal+19

Libervia is a modular XMPP-based communication suite offering chat, microblogging, file sharing, and other social features across web, desktop, and CLI interfaces.

Activity unknown

Alternative to:

Element Matrix (Hosted)+19

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

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Postfix+11

OpenTalk is an open-source video conferencing platform offering GDPR-compliant SaaS and self-hosted deployments with features like recording, whiteboards, breakout rooms, polls and telephone dial-in.

Activity unknown

Alternative to:

Zoom+18