Sync-in Server tackles a challenge many teams face when they want file synchronization and collaboration but cannot or prefer not to trust public cloud providers. It offers a self-hosted platform that goes beyond basic file sync — combining fine-grained access control, enterprise-grade authentication, and real-time collaborative editing with well-known open source office suites.
What Sync-in server provides and its architecture
At its core, Sync-in Server is a TypeScript-based backend platform designed for on-premises or private cloud deployment. It manages file storage, synchronization, and collaboration with a focus on data sovereignty and open standards.
The architecture leverages a modular design that integrates several key components:
Fine-grained RBAC (Role-Based Access Control): Users and groups can be assigned permissions at the space and share level. This allows granular control over who can access or modify specific files or folders.
Authentication via OIDC and LDAP with MFA support: Sync-in supports enterprise authentication systems, allowing organizations to integrate their existing identity providers. This is critical for security and usability in corporate environments.
Real-time collaborative editing: The server integrates with Collabora Online and OnlyOffice, two open source office suites that enable live document editing within the platform.
WebDAV protocol support: This exposes the file system over a widely supported network protocol, allowing compatibility with many clients and tools.
Full-text search with deep document indexing: Beyond file metadata, the platform indexes document content, improving search capabilities.
Cross-device synchronization: Desktop and CLI clients synchronize files in real time, keeping data consistent across user devices.
The entire stack is implemented in TypeScript, which means strong typing and modern JavaScript features are leveraged for maintainability and developer productivity. The project is distributed under AGPL-3.0, emphasizing open source principles.
What makes Sync-in’s permission model and collaboration integration stand out
The defining technical strength of Sync-in Server is how it combines a robust, fine-grained RBAC system with real-time collaboration capabilities.
Most self-hosted file sync solutions offer simple share links or folder-level permissions. Sync-in goes deeper by enabling permission management at multiple levels (spaces and shares), supporting complex organizational policies. This is essential in multi-tenant or enterprise scenarios where data access must be tightly controlled.
The RBAC system is tightly integrated with authentication providers (OIDC/LDAP) and supports multi-factor authentication, which enhances security without sacrificing flexibility. The code handling these aspects is surprisingly clean for such a complex domain, with clear separation of concerns between auth, permission checks, and file operations.
On the collaboration front, Sync-in does not reinvent the wheel but integrates with Collabora Online and OnlyOffice. These integrations are non-trivial because they require managing real-time document editing sessions, syncing changes back to the file storage, and enforcing permissions in real time. Sync-in’s architecture ensures these office suites can operate seamlessly within its permission spaces.
Supporting WebDAV means that legacy clients and a broad range of tooling can access the file system without custom clients, which is a practical tradeoff that boosts compatibility.
The full-text search with deep document indexing shows attention to usability—searching inside documents instead of just file names is a big plus for end users.
Tradeoffs include added complexity in deployment and operation. Running Collabora or OnlyOffice alongside the server requires additional resources and configuration, which might be overkill for simple file sync needs. Also, the TypeScript backend means the platform depends on a Node.js environment, which might not suit every IT infrastructure.
Explore the project
Since no quickstart commands are provided, the best way to get started is by exploring the repository and documentation.
The main source code is organized around the server entry point, middleware for authentication and permissions, and modules handling storage, search indexing, and collaboration integration.
The README and docs highlight configuration options for authentication providers (OIDC/LDAP), setting up RBAC policies, and integrating with Collabora/OnlyOffice. These are critical to understand before deployment.
Key areas to look at:
src/auth/for authentication logicsrc/permissions/for RBAC implementationsrc/collaboration/for integration with online editors- Configuration files describing server setup and external service connections
Understanding the WebDAV interface is also useful if you plan to use or extend the protocol support.
Verdict
Sync-in Server is well suited for teams or organizations needing a self-hosted file synchronization platform that does not compromise on security or collaboration features.
It’s particularly relevant for enterprises with strict data governance policies requiring RBAC, OIDC/LDAP authentication, and MFA. The real-time integration with Collabora and OnlyOffice makes it attractive for users who want cloud-like document collaboration but hosted on their own infrastructure.
The tradeoff is complexity: setting up and maintaining the platform requires some infrastructure knowledge, especially to run the integrations smoothly. If your requirements are simpler—basic file sync without collaboration or enterprise auth—lighter tools might be more practical.
Overall, Sync-in Server offers a solid, open source alternative to cloud file sync services, with strong technical foundations and sensible architectural decisions. It’s worth understanding for anyone building or operating self-hosted file collaboration solutions.
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→ GitHub Repo: Sync-in/server ⭐ 1,146 · TypeScript