For a peer to peer file synchronization tool, the first results are syncthing/syncthing, bcpierce00/unison and spacedriveapp/spacedrive (Spacedrive is a decentralized file manager that synchronizes files across your own devices without a central server, so it fits your goal of a peer-to-peer sync tool, though its primary focus is on aggregating multiple storage sources rather than just folder sync). tonyantony300/alt-sendme and canton7/synctrayzor round out the shortlist. Compare the match explanations and check the project documentation against your requirements.
These open-source utilities enable secure, decentralized file sharing and folder synchronization across multiple computing devices.
Syncthing is a decentralized file synchronization engine that maintains consistent data states across multiple devices through peer-to-peer mesh networking. It operates as a background daemon that automatically replicates file creations, modifications, and deletions between trusted nodes without requiring central servers. By utilizing content-addressable block indexing and block-level delta synchronization, the system identifies and transfers only the modified segments of files, ensuring efficient data propagation across heterogeneous environments. The project distinguishes itself through a s
Syncthing is a decentralized peer-to-peer file synchronization engine that replicates changes across your devices without a central server, covering peer-to-peer sync, encryption, selective sync, LAN discovery, versioning, and NAT traversal — exactly the self-hosted tool this search is after.
Unison is a bidirectional file synchronization tool that keeps two copies of a directory identical by automatically propagating changes in both directions. It operates over an encrypted SSH transport layer, allowing secure synchronization between different hosts and operating systems without a central server. The tool uses a bidirectional reconciliation engine to compare replicas and compute a minimal set of actions for agreement, handling both automatic merging of non-conflicting changes and clear reporting of conflicts that require manual resolution. Unison optimizes transfers by sending on
Unison is a bidirectional file-synchronization tool that operates over encrypted SSH connections between two hosts without a central server, directly addressing your need for decentralized device-to-device sync and conflict handling, though it lacks automatic LAN discovery and relay traversal features.
Spacedrive is a decentralized storage client that functions as a distributed file manager, aggregating local, cloud, and network storage into a single virtual filesystem. It operates on a local-first design, prioritizing offline availability by caching metadata and file chunks locally before synchronizing them across devices. By coordinating data access without relying on a central server, it enables users to maintain a private and secure storage network across their own hardware and cloud accounts. The platform distinguishes itself through a virtual storage layer that maps disparate physical
Spacedrive is a decentralized file manager that synchronizes files across your own devices without a central server, so it fits your goal of a peer-to-peer sync tool, though its primary focus is on aggregating multiple storage sources rather than just folder sync.
alt-sendme is an accountless peer-to-peer file transfer tool designed for sending files and folders directly between devices. It operates as a decentralized sharing service that utilizes portable access tickets for identity exchange instead of centralized user accounts. The project distinguishes itself through NAT and firewall traversal capabilities, using UDP hole punching and relay-based fallback routing to establish direct connections between remote devices. It supports multi-device data broadcasting, allowing a single file or folder to be shared with multiple recipients simultaneously thr
alt-sendme is a peer-to-peer file transfer tool with NAT traversal and encryption, but it focuses on one-time file transfers rather than continuous folder synchronization, so it only partly fits the core sync requirement.
SyncTrayzor is a native Windows tray wrapper and management interface for Syncthing. It functions as a process manager that ensures the synchronization service starts automatically upon user login and remains active in the background. The project provides a built-in browser to render the Syncthing web interface and includes a specialized conflict resolver tool to identify and fix versioning mismatches between synchronized files. It integrates directly into the system tray to provide service status updates and desktop notifications. Capability areas include synchronization monitoring for trac
SyncTrayzor is a Windows tray wrapper and interface for Syncthing, not a standalone peer-to-peer sync tool — it manages an external sync engine rather than providing synchronization itself, so it falls short of the full decentralized file-syncing tool you are looking for.
Toxcore is a peer-to-peer networking library that implements a decentralized communication protocol for secure messaging and media calls without the use of central servers. It provides a core engine for establishing direct encrypted connections between devices using a public-key identity system where unique identifiers serve as both addresses and authentication keys. The project features a decentralized network architecture that utilizes a distributed hash table for peer discovery and Kademlia-based routing to locate participants. To maintain connectivity across restrictive network environmen
Toxcore is a peer-to-peer networking library for secure messaging and media calls, not a file synchronization tool—it lacks the folder syncing, selective sync, and versioning capabilities needed for device-to-device file sharing.
Remotely Save is a cloud storage synchronization tool and backup manager designed to keep local files and application data consistent across desktop and mobile devices. It functions as a cross-platform synchronizer that mirrors local data to remote servers using S3 and other cloud protocols. The project focuses on privacy and security through end-to-end encryption, which secures files with a user-defined password before they are uploaded to remote cloud services. It ensures data remains private on third-party servers by applying symmetric client-side encryption. The system includes capabilit
Remotely Save syncs files to cloud storage (S3) rather than directly between devices, so it is not a peer-to-peer synchronisation tool and does not match your request for decentralized device-to-device sharing.
This project is a peer-to-peer networking tool and communication client designed for exchanging messages and sharing screen control between computers without a central server. It functions as a decentralized system for exchanging data and control signals directly between nodes. The application uses WebRTC for peer-to-peer messaging and remote desktop administration. It incorporates STUN-based NAT traversal and rendezvous servers to establish direct connections between peers hidden behind restrictive firewalls or routers. The software provides capabilities for remote desktop control, includin
This is a peer-to-peer remote desktop and messaging tool with WebRTC and NAT traversal, but it does not provide folder synchronization, selective sync, versioning, or cross-platform file sharing—it is built for remote control and chat, not file synchronization between devices.
n2n is a peer-to-peer VPN that creates an encrypted mesh network by establishing layer 2 overlay networks. It uses UDP tunneling to connect remote computers into a shared virtual local area network, allowing devices to communicate as if they were on the same physical Ethernet switch. The system utilizes a centralized signaling registry and federated coordination nodes to facilitate peer discovery and node registration. It implements NAT traversal through UDP hole punching and UPnP port mapping, while using supernode relay routing to ensure connectivity when symmetric NATs prevent direct peer-
n2n creates a peer-to-peer encrypted VPN mesh for network connectivity, but it does not handle file synchronization, selective sync, versioning, or device-to-device file sharing — it is a networking layer rather than a peer-to-peer file sync tool as requested.
Iroh is a peer-to-peer networking stack and distributed system designed for secure direct connections, content-addressed storage, and synchronized data sharing. It provides a foundation for decentralized applications by combining a QUIC-based networking layer with primitives for distributed state and data transfer. The project distinguishes itself through a comprehensive suite of decentralized capabilities, including a distributed data store using conflict-free replicated data types for collaborative synchronization and a content-addressed storage system for verifiable, resumable transfers of
Iroh is a peer-to-peer networking library and distributed systems foundation, not a ready-to-use file synchronization tool — it supplies many of the underlying capabilities (secure connections, NAT traversal, CRDT syncing) but requires custom development to achieve folder sync and device-to-device sharing, so it is a building block rather than the direct application you are looking for.
This project is a full-featured BitTorrent client library and protocol implementation. It provides the core components necessary for peer-to-peer file sharing, including a networking stack that supports the BitTorrent specification, tracker communication, and swarm management. A primary differentiator is the inclusion of a virtual filesystem that allows torrents to be mounted as read-only drives. This system enables on-demand content streaming, where specific data pieces are fetched from the network only when a read request occurs, rather than requiring the entire archive to be downloaded fir
anacrolix/torrent is a BitTorrent client library for peer-to-peer file transfer, but it is a low-level building block rather than a self-contained folder-synchronization tool with selective sync, versioning, or easy device-to-device sharing — it powers torrent downloads, not continuous folder sync.
Seafile is a self-hosted file synchronization and sharing platform that provides a central server for maintaining file consistency across multiple devices. It functions as a cloud storage management system and a collaborative document suite, integrating tools for real-time teamwork and shared file management. The platform distinguishes itself through a metadata-driven file organizer that uses extensible properties and hierarchical tags instead of traditional folder structures. It includes client-side encrypted storage to protect private data using user-defined passwords before files leave the
Seafile is a self-hosted file sync and sharing platform, but it uses a central server to coordinate devices rather than true peer-to-peer direct device-to-device sync, so it fits the broader category but not the specific P2P architecture you want.
| Repository | Stars | Language | License | Last push |
|---|---|---|---|---|
| syncthing/syncthing | 85.4K | Go | MPL-2.0 | |
| bcpierce00/unison | 5.1K | OCaml | gpl-3.0 | |
| spacedriveapp/spacedrive | 38.3K | Rust | NOASSERTION | |
| tonyantony300/alt-sendme | 5.4K | TypeScript | agpl-3.0 | |
| canton7/synctrayzor | 6.2K | C# | MIT | |
| irungentoo/toxcore | 8.8K | C | GPL-3.0 | |
| remotely-save/remotely-save | 6.8K | TypeScript | other | |
| miroslavpejic85/p2p | 4K | C# | mit | |
| ntop/n2n | 7K | C | GPL-3.0 | |
| n0-computer/iroh | 7.9K | Rust | apache-2.0 |