17 Best Open Source Microsoft Teams Alternatives
A curated collection of the 17 best open source and self-hosted alternatives to Microsoft Teams in 2026.
Looking for a free, privacy-friendly, or self-hosted replacement for Microsoft Teams in 2026? The top open-source alternative is Macro Chat — Team chat with AI agents and unified workspace.
Other highly rated open-source Microsoft Teams alternatives include Rocket.Chat, Buzz and Mattermost.
Team chat with AI agents and unified workspace
Macro is a modern team collaboration platform that unifies chat, email, tasks, and AI agents into a single workspace. Designed for teams that want to reduce context switching, Macro offers inline threads, instant @mention sharing, and AI-powered assistance with full workspace context. - Inline threads & forum discussions: Keep conversations organized with threaded replies directly below messages. - @mention sharing: Instantly share docs, tasks, or email threads with channel members without permission dialogs. - Unified inbox: Combine email, chat, and tasks in one place for streamlined workflows. - AI agents with context: Type @Macro to summon an agent that summarizes missed conversations, drafts replies, or answers questions using your workspace data. - Built-in tasks & docs: Create and manage tasks and documents natively within the chat interface. - Unified search: Search across channels, email, docs, and tasks with a single query. - Open source (AGPLv3): Self-hostable and auditable, ensuring full control over your data. - Enterprise-ready: Includes CRM, calls, and advanced collaboration tools in a single seat. Macro is open source under the AGPLv3 license and can be self-hosted for complete data control. The platform prioritizes security with private, encrypted workspace data and offers flexible deployment options. For teams preferring a managed solution, Macro provides a hosted version with all features included.
Secure team chat with voice, video & AI
Rocket.Chat is a secure, open-source communication platform that centralizes real-time messaging, voice, video, and AI capabilities for teams and organizations. Designed for mission-critical operations, it offers robust data privacy, sovereignty, and compliance features. - Unified Communication: Real-time messaging, voice and video calls in a single platform - Multi-Environment Deployment: Cloud, on-premises, or air-gapped environments - Data Privacy & Sovereignty: End-to-end encryption, access controls, and compliance features - AI Integration: Privacy-first AI capabilities for workflow optimization - Cross-Organization Collaboration: Secure communication across teams and external stakeholders - Governance & Monitoring: Complete messaging governance and audit trails - Integration Hub: Connect tools, custom apps, and processes into one platform - Accessibility Compliance: WCAG 2.1 Level AA conformance for regulated procurement Rocket.Chat is fully open-source (MIT license) and can be self-hosted on any infrastructure. The platform supports Docker, Kubernetes, and traditional server setups. Enterprise-grade security features include SSO, 2FA, and granular permission controls. Documentation and developer guides are available for custom deployments and integrations.
Collaborative workspace for human and AI agent teams
Buzz is a collaborative workspace designed for human and AI agent teams to work together seamlessly. It consolidates communication, project management, and development tools into a single shared space. - Unified Collaboration: Chat with teammates and specialized agents in shared rooms, keeping context, decisions, and next steps in one place. - Agent Integration: Invite and manage AI agents tailored to your workflows, enabling them to collaborate with your team’s agents. - Project Management: Turn discussions into plans, code, reviews, and PRs without switching between tools. - Open Source: Fully open source project with community-driven development. - Enterprise Ready: Waitlist available for an enterprise version with company-wide access and advanced agent management. Buzz is an open source project available on GitHub. It can be self-hosted for full control over data and infrastructure. The project is built by Block and supports GDPR compliance.
Secure collaboration platform for mission-critical teams
Mattermost is an open-source collaboration platform designed for mission-critical work environments where security, compliance, and operational sovereignty are paramount. - Secure Collaboration: End-to-end encrypted messaging with granular access controls and audit logging - Mission-Critical Workflows: Built-in Playbooks for repeatable processes and incident response - AI Integration: Enterprise-grade AI capabilities with agentic workflows and MCP support - Multi-Domain Security: Air-gapped, on-prem, and private cloud deployment options - Interoperability: Native integrations with Microsoft Teams, Atlassian, GitLab, and 1,000+ other tools - Compliance Ready: SOC 2, HIPAA, FedRAMP, and ITAR compliant deployments - Developer Tools: Built-in code review, CI/CD pipelines, and API-first architecture - Global Trust: Deployed by governments, militaries, and Fortune 500 enterprises Mattermost is available as both a cloud-hosted solution and self-hosted open-source software. The self-hosted version can be deployed on any infrastructure with Docker, Kubernetes, or bare metal installations. Supports PostgreSQL, MySQL, and enterprise-grade security configurations. Full documentation available at docs.mattermost.com.
Self-hosted productivity platform for secure file sharing
Nextcloud is a self-hosted productivity platform that provides a safe home for all your data. It offers secure file sharing, collaboration tools, and a suite of integrated applications like calendars, contacts, mail, and more. - Secure File Storage & Sharing: End-to-end encrypted file storage with granular access controls and file versioning. - Collaboration Suite: Built-in tools for document editing, calendars, contacts, mail, and video conferencing. - App Ecosystem: Extensible with over 200+ community and official apps for enhanced functionality. - Self-Hosted & Private: Full control over your data with no third-party access or tracking. - GDPR Compliant: Designed with privacy in mind, meeting strict EU data protection regulations. - Cross-Platform Support: Available on desktop, mobile, and web with seamless synchronization. - Open Source: Transparent codebase with active community and enterprise support options. - Enterprise Features: Advanced security, scalability, and compliance tools for business use. Nextcloud is built with PHP and uses a relational database (MySQL, PostgreSQL, MariaDB) for storage. It supports Docker, Snap packages, and traditional server installations. The platform is highly scalable and can be deployed on-premises or in cloud environments. Comprehensive documentation and community support are available for self-hosting setups.
Host encrypted video conferences directly in your browser, deploy on your own servers, or integrate into applications - all with this powerful open source platform.
Host encrypted video conferences directly in your browser, deploy on your own servers, or integrate into applications - all with this powerful open source platform.
Organized team chat for distributed teams
Zulip is a powerful team chat application that organizes conversations into streams and topics, making it easier to follow discussions and reduce noise. Designed for distributed teams, it combines the flexibility of chat with the organization of email threads. - Stream-based organization: Conversations are structured into streams and topics for better clarity - Cross-platform support: Available as desktop, mobile, and web applications - Powerful search: Advanced search capabilities to find any conversation or file - Integrations: Extensive API and integration support for popular tools - Privacy controls: Strong privacy features including end-to-end encryption options - Self-hosting: Full control over your data with self-hosted deployment - Scalability: Suitable for teams of all sizes from small groups to large organizations - Open source: Community-driven development with transparent codebase Zulip is open source and can be self-hosted on your own infrastructure. The project provides comprehensive documentation for installation and maintenance. Cloud hosting is also available through Zulip Cloud for teams that prefer a managed solution. The software is built with Python, Django, and PostgreSQL, making it suitable for most server environments.
Secure decentralized team messaging & collaboration
Element is a Matrix-based end-to-end encrypted messenger and secure collaboration app. It operates on the decentralized Matrix network, enabling interoperability and easy connections between different services. - End-to-end encryption for all communications - Decentralized architecture built on the open Matrix protocol - Self-hosting capability for digital sovereignty - Interoperability with other Matrix-compatible services - Cross-platform support (web, desktop, mobile) - Group messaging & collaboration tools - File sharing & voice/video calls - Enterprise-grade security with compliance options Element is built on the Matrix open standard and can be self-hosted for complete data control. The platform supports various deployment options including Docker containers and Kubernetes. For organizations requiring managed services, Element Matrix Services provides hosted solutions with enterprise support. Matrix protocol ensures data portability and interoperability across different Matrix clients and servers.
Immersive 2D virtual office & event platform
WorkAdventure is an open-source platform that transforms remote collaboration through immersive 2D virtual environments. Whether you need a virtual office for team coordination, a venue for virtual events, a digital classroom for learning, or an innovative HR recruitment space, WorkAdventure delivers interactive experiences that boost engagement and productivity. - Virtual Offices: Create digital workspaces where teams can collaborate in real-time with proximity-based interactions - Virtual Events: Host conferences, workshops, and meetups in customizable 2D worlds with networking capabilities - Digital Classrooms: Build virtual campuses for e-learning with gamified experiences and interactive teaching spaces - HR & Recruitment: Design branded virtual career fairs and onboarding experiences for talent acquisition - Custom World Building: Design and deploy your own 2D maps with assets and branding using the built-in editor - Self-Hosting: Full control over your data with self-hosted deployment options - Multi-Language Support: Available in multiple languages including English, French, and Portuguese - Open Source: Community-driven development with transparent codebase WorkAdventure is built with TypeScript and uses WebRTC for real-time communication. The platform can be self-hosted on your own infrastructure with comprehensive documentation available. It supports Docker deployment and provides guidelines for scaling virtual environments. The open-source nature allows for customization and integration with existing systems.
Self-hosted Slack alternative with code access
Campfire is a self-hosted group chat system designed for teams who want to avoid recurring subscription fees. Built by Basecamp, it offers a familiar Slack-like interface with essential features like direct messages, @mentions, and mobile support. - Self-hosted: Install on your own server or cloud provider (AWS, DigitalOcean, Hetzner, etc.) - No subscriptions: One-time setup with no ongoing fees - Essential chat features: Rooms, DMs, @mentions, dark mode, and mobile PWA support - Customizable: Full access to source code under MIT License for modifications - Private rooms: Create private or public rooms for different teams or projects - Air-gapped support: Works offline or on isolated networks - Automatic updates: Optional daily update checks with manual override - Chatbots: Simple HTTP API for integrating custom chatbots - Installation: Single command via ONCE CLI (curl https://get.once.com/campfire | sh) - System requirements: Scales from 250 users (2GB RAM, 1CPU) to 10,000 users (64GB RAM, 32CPU) - Compatibility: Runs on laptops, local servers, or cloud infrastructure - Mobile: Progressive Web App (PWA) with push notifications and badges - License: MIT License (free and open source)
Open-source Slack and Notion alternative
Colanode is a modern, all-in-one collaboration platform designed for teams seeking a flexible and self-hostable alternative to Slack and Notion. Built with local-first principles and powered by CRDTs, it ensures seamless synchronization and conflict-free collaboration across devices. - Local-first architecture: Save work to your device first, sync in the background for offline access and reduced latency. - Conflict-free collaboration: Powered by CRDTs (Conflict-free Replicated Data Types) for smooth multi-player editing without conflicts. - Self-hosting or cloud: Deploy on your own infrastructure or use the managed cloud version—your data, your choice. - Integrated workspace: Combine chat, rich text pages, databases, and file management in a single platform. - Real-time chat: Communicate with individuals or teams through channels with instant messaging. - Rich text pages: Create documents, wikis, and notes using an intuitive editor similar to Notion. - Structured databases: Organize information with custom fields, dynamic views (table, kanban, calendar), and relational data. - File management: Securely store, share, and manage files within dedicated workspaces. Colanode is open-source and designed for easy self-hosting. It supports deployment on various platforms including Docker, Kubernetes, and bare metal. Detailed self-hosting guides and documentation are available to help you get started. The platform is built with modern web technologies and prioritizes performance, security, and scalability.
Privacy-focused Matrix client
Cinny is a modern, privacy-focused Matrix client that prioritizes simplicity and performance. Built with web technologies, it offers a clean interface while ensuring your data remains under your control. - Privacy-first: End-to-end encryption and no tracking - Lightweight: Fast and resource-efficient - Cross-platform: Works on web, desktop, and mobile - Customizable: Themes and plugins for enhanced functionality - Self-hostable: Full control over your data - Matrix protocol: Interoperable with other Matrix clients - Open source: Community-driven development Cinny is built with TypeScript and React, making it easy to self-host on any server. The project provides Docker images and detailed deployment guides for seamless setup. All data is stored on your own infrastructure, ensuring maximum privacy and compliance with data protection regulations.
Secure end-to-end encrypted messenger for organizations
Wire is a trusted secure communication platform designed for organizations worldwide. Built with invisible end-to-end encryption, Wire ensures all conversations and data remain private and protected at all times. - End-to-End Encryption: All messages, calls, and files are encrypted by default, ensuring complete privacy. - Flexible Deployment: Choose from cloud, on-premises, or hybrid deployment to meet organizational needs. - Enterprise-Grade Security: SSO, granular permissions, and compliance-ready security for regulated environments. - Cross-Platform Support: Available on desktop, mobile, and web for seamless collaboration. - Scalable Collaboration: Designed for teams of all sizes, from SMBs to large enterprises and governments. - Intuitive Interface: User-friendly design that combines speed and simplicity with enterprise security. - Open Source: Transparent development with auditable code available on GitHub. - Compliance Ready: Meets strict regulatory requirements for data protection and sovereignty. Wire offers flexible deployment options including self-hosted solutions for organizations requiring full data control. The open-source server components allow for custom deployment in private cloud or on-premises environments. Technical documentation and developer resources are available for self-hosting and integration.
All-in-one community platform with AI agents
Mezon is an all-in-one community platform designed for live interaction, collaboration, and entertainment. Whether you're gaming with friends, organizing a worldwide community, or building a business hub, Mezon provides the tools to connect, engage, and monetize seamlessly. - Super-Fast Messaging: Zero-limit, instant delivery for seamless communication. - Voice Channels: Engage in real-time voice conversations with friends or community members. - Clan Customization: Create and personalize your own community space for discussions, hobbies, or trends. - In-Community Payments: Send money instantly, reward creators, and shop with zero platform fees. - AI Agents: Voice AI for summarizing conversations, Assistant Mode, and Bot Shadow Mode for text channel summaries. - Enterprise Integrations: Connect with global customers and deliver large-scale experiences. - Cross-Platform Access: Available on mobile (iOS/Android) and desktop. Mezon is a cloud-based platform with no self-hosting option. The open-source components and APIs are available for developers to integrate and extend functionality. For more details, visit the Developer Documentation.
Collaborative email for teams to get work done
UnInbox is a modern collaborative email platform designed for teams to manage shared inboxes efficiently. It eliminates email chaos with shared spaces, infinite custom addresses, and per-email workflows that track task completion. - Shared Spaces: Collaborate on conversations with team comments and replies from shared addresses (e.g., support@, sales@, admin@) - Infinite Addresses: Create unlimited custom email addresses for any department or use case - Per-Email Workflows: Track email statuses (e.g., pending, in-progress, done) to ensure nothing falls through the cracks - No More FWD/RE Chains: Reduce email clutter with threaded discussions in shared spaces - Transparent Pricing: Free tier available with Pro ($12/user/month) and Enterprise plans with dedicated support - Open Source: Self-hostable with SMTP and API access for advanced users UnInbox is open-source and can be self-hosted for full data control. The platform offers SMTP and API access, making it suitable for teams prioritizing privacy and customization. Enterprise plans include dedicated instances, SAML SSO, and 10-year email retention for compliance needs.
Secure open-source messenger for professionals
Twake Chat is a secure and private-by-default messenger designed for professional communication. Built on the decentralized Matrix protocol, it ensures high levels of security and privacy while offering features like end-to-end encryption, multi-account support, and cross-device synchronization. - End-to-End Encryption (E2EE): Secure conversations with customizable security levels. - Multi-Account Support: Switch between personal and work accounts seamlessly. - Cross-Platform Sync: Synchronize messages and data across all devices (mobile, tablet, laptop). - Matrix Protocol Integration: Communicate across platforms like Telegram, Discord, and Signal via bridges. - Jitsi Integration: Built-in videoconferencing for improved collaboration. - Corporate Directory (SSO): Facilitate communication with contacts from phone books and corporate directories. - On-Premises Deployment: Host Twake Chat on your own infrastructure for enhanced security and performance. - User-Friendly Interface: Simple registration, usage, and maintenance with strong community support. Twake Chat is powered by the Matrix protocol and can be deployed on-premises or in the cloud. The open-source server (ToM-server) is available on GitHub, and the project offers technical documentation for self-hosting. Mobile apps are available for both Android and iOS.
Open source chat server for mobile and web apps
SAMA is a next-generation open source chat server designed for mobile and web applications. It provides a secure, scalable, and easy-to-use messaging solution with built-in end-to-end encryption and clustering capabilities. - Messaging: Rich media messages, status indicators, private/group chats, file attachments, and message history API - User Management: Authorization, profile editing, user search, and block list functionality - Multi-Device Support: Seamless connectivity across multiple devices with online/offline message delivery - Last Activity Tracking: Server-side tracking of online/offline status with subscription API - Push Notifications: APNS, FCM, and web push notifications for offline message delivery - Clustering: Built-in support for large-scale deployments and high user loads SAMA is open source and can be self-hosted. The server is built with modern technologies and supports clustering out of the box. Documentation and API references are available for developers looking to integrate or customize the solution. The project provides both backend (sama-server) and frontend (sama-client) components.
About Microsoft Teams
Microsoft Teams is a unified communication and collaboration platform that integrates chat, video conferencing, file sharing, and app integration into a single workspace. Built for teams of all sizes, it combines real-time collaboration tools with AI-powered features like automated meeting notes, intelligent video technology, and workflow automation.
Key Features of Microsoft Teams
- AI-powered meetings: Automated meeting notes, AI summarization, and intelligent video technology
- Video conferencing: HD video calls, screen sharing, and custom backgrounds
- Chat and collaboration: Instant messaging, file sharing, and team collaboration
- Integrated apps: Access to Microsoft 365 apps and third-party integrations
- Cross-platform support: Available on desktop, web, and mobile devices
- Security and compliance: Enterprise-grade security with GDPR compliance
- Workforce management: Staff scheduling, hot desking, and contact center solutions
- Multi-purpose use: Solutions for education, manufacturing, financial services, and frontline workers
Tech / Self-Hosting
- Cloud-based: Primarily offered as a SaaS solution with Microsoft 365 integration
- No self-hosting option: Microsoft Teams is not available for self-hosting
- Enterprise features: Advanced security, compliance, and management tools for business users