Open Source Nextcloud Alternatives

Rocket.Chat is an open source communication platform built for organizations that can't hand their data to a third-party cloud. It brings together real-time messaging, voice and video calls, screen sharing, and AI-assisted workflows into a single environment you host and control entirely.

Security is central to the design. It supports on-premises, air-gapped, and secure cloud deployments, and has been used on classified U.S. government networks including NIPRNet, SIPRNet, and JWICS. It holds DoD Authorization to Operate (ATO) up to Impact Level 6. Few commercial team chat tools come close to that clearance level.

Beyond defense and intelligence, it fits any organization where data sovereignty matters: government agencies, critical infrastructure operators, financial institutions, and enterprises subject to strict regulatory requirements. The Swedish Electrical Safety Board and EU agency eu-LISA both use it for secure internal and cross-organizational collaboration.

Core capabilities include fully encrypted conversations, granular access controls, fine-grained data retention policies, and comprehensive audit logs. Federated communication lets teams coordinate across organizational or jurisdictional boundaries without routing data through external services.

The architecture is extensible. Teams can install pre-built apps or build custom integrations to fit specific workflows, without being locked into a vendor's roadmap. If you want something lighter, Mattermost is a comparable self-hosted option worth considering. The built-in AI features handle routine tasks and surface relevant information during active conversations — for teams that want a standalone AI layer instead, LLMChat takes a different approach.

Filestash is a versatile, open-source file management solution designed for enterprises. It offers a unified interface to access and manage files across various storage backends, including S3, SFTP, FTP, WebDAV, Samba, and many more.

Key features include:

1. Universal File Manager: Browse, organize, and share files across multiple storage solutions through a single intuitive interface.

2. SSO Integration: Seamlessly integrates with corporate SSO systems like LDAP, SAML, and OIDC for secure and familiar authentication.

3. White-Label Solution: Customize Filestash's appearance to match your company branding and deploy it as your own solution.

4. Extendable Architecture: Utilize plugins to extend functionality and adapt to specific business needs. Custom plugin development is available for specialized requirements.

5. Security & Compliance: Maintain high security standards with activity logs and audit trails, allowing you to monitor user actions and protect confidential data.

6. Wide Range of Supported Backends: Compatible with popular storage solutions like S3, SFTP, FTP, WebDAV, Samba, Minio, Azure Blob, Git, and many others.

7. Enterprise-Ready: Trusted by notable organizations including MIT, DHL, Schneider Electric, and others.

Filestash offers both an open-source version for self-deployment and an enterprise version with additional features and support. It's an ideal solution for businesses looking to streamline file management across diverse storage systems while maintaining security and compliance.

Transform how you organize and collaborate on files with this powerful self-hosted solution that goes beyond traditional file syncing. Built for teams who need complete control over their data while maintaining seamless collaboration.

Key advantages:

• AI-powered file organization - Automatically generate descriptions, tags, and extract key information from your files
• Custom file properties - Add metadata like owner, status, and security level to make files easily searchable and filterable
• Flexible viewing options - Create table, gallery, kanban, and map views based on your file properties
• Real-time collaboration - Built-in document editor (SeaDoc) with co-editing, revision tracking, and review workflows
• Granular permissions - Control access at folder and sub-folder levels with read/write, read-only, and preview permissions
• Enterprise security - Advanced encryption, comprehensive audit logs, and file history recovery
• Multi-level tagging - Organize tags in hierarchical structures for better categorization

Perfect for teams seeking:

• Complete data ownership and privacy
• Advanced file organization capabilities
• Seamless collaboration without vendor lock-in
• Enterprise-grade security and compliance features

Trusted by over 1 million users worldwide, this solution offers the perfect balance of powerful features and data sovereignty.

OpenCloud is a file management and collaboration platform built for organizations that need full control over their data. It's developed by the Heinlein Group, a Berlin-based open source IT company with three decades of experience. The platform targets public sector bodies, research institutions, educational organizations, and businesses that can't afford to hand their data to a third-party cloud provider.

At its core, OpenCloud handles what tools like Nextcloud or Seafile also tackle: storing, syncing, and sharing files across teams. What sets it apart is its cloud-native architecture designed for high data volumes and large user counts, combined with a strong emphasis on GDPR compliance and zero-trust security principles.

Key capabilities include:

• Integrated office suite for real-time document collaboration without switching tools
• Encryption and secure versioning that protects against ransomware
• Two-factor authentication and flexible access rights management
• On-premise or SaaS deployment through selected partners, depending on your infrastructure needs
• Mobile accessibility with a barrier-free interface suited for distributed teams

For IT administrators, the platform is designed to slot into existing infrastructure without heavy customization. Installation is straightforward, and the system handles growing teams without performance degradation.

OpenCloud sits in the same cloud file sync and share space as Dropbox alternatives, but with a self-hostable model that keeps data under your organization's control. The zero-trust approach means access is verified continuously, not just at login. That makes it a practical fit for regulated industries or public institutions where data residency requirements are non-negotiable.

Sync-in is an open-source file storage and collaboration platform that puts you in complete control of your data. Unlike traditional cloud services, you host everything on your own infrastructure, ensuring data sovereignty and compliance with regulatory requirements.

Key features include:

• Real-time collaborative editing with Collabora Online and OnlyOffice integration
• Advanced file synchronization across Windows, macOS, and Linux devices
• Collaborative spaces for team organization with granular permissions
• Smart search with full-text content indexing across document types
• Secure sharing with customizable access controls and expiration dates
• WebDAV integration for seamless file explorer mounting

The platform combines security by design with modern performance, offering a scalable architecture suitable for individual users to enterprise deployments. Built with transparency at its core, Sync-in benefits from continuous community contributions while maintaining the highest security standards.

Whether you need to collaborate with external partners through the guest system, manage complex file workflows, or ensure regulatory compliance, Sync-in provides a powerful alternative to proprietary cloud storage solutions without compromising on functionality or user experience.

Secure your professional data with an open source encrypted storage solution that puts privacy first. Store, share, and collaborate on files with complete control over your data through on-premises deployment options.

Key features include:

• End-to-end encryption for maximum security with unique keys for each file
• Shared Drive functionality for seamless team collaboration
• Built-in office suite with OnlyOffice integration for creating documents, presentations, and spreadsheets
• Advanced search capabilities to quickly find files by content, name, or sender
• Flexible access controls with public or protected link sharing
• Self-hosted deployment to maintain complete data sovereignty

Perfect for businesses seeking privacy-focused file storage without compromising on functionality. The platform combines enterprise-grade security with an intuitive interface, making it easy for teams of any size to collaborate while keeping sensitive data protected. Built by LINAGORA, a leader in European open source solutions.

Firefiles revolutionizes cloud storage management by offering a unified platform for all your storage needs. Here's what makes Firefiles stand out:

1. Multi-Provider Support: Seamlessly integrate with popular cloud storage providers like Firebase, AWS, Digital Ocean, Backblaze, and more.

2. Open Source: Fully open-sourced on GitHub, ensuring transparency and community-driven development.

3. Enhanced Security: Offers superior security and privacy compared to traditional cloud storage solutions.

4. User-Friendly Interface:

   • Intuitive dashboard for managing multiple drives
   • Light and dark UI themes
   • File preview functionality directly in the browser

5. Efficient File Management:

   • Easy simultaneous upload of multiple files
   • Quick downloads with a single click
   • File preview without downloading

6. Customizable: Set up your cloud drive with the backend of your choice.

7. Team Collaboration: Invite team members to your cloud drives (coming soon).

8. Cross-Platform: Available for MacOS, Windows, and Linux.

Firefiles is designed to be the last cloud storage solution you'll ever need, combining the flexibility of multiple providers with the simplicity of a single, user-friendly interface. Whether you're an individual user or part of a team, Firefiles offers a seamless experience for all your file storage and management needs.