syncthing/syncthing
Syncthing
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 security-first architecture that relies on mutual TLS authentication to verify device identity, ensuring that all connections are cryptographically bound to trusted certificate fingerprints. It supports flexible synchronization modes, including bidirectional replication, unidirectional mirroring for backups, and reference-based enforcement. For added privacy, the system provides folder-level encryption for untrusted devices and allows for granular control over network traffic, including the ability to restrict operations to local networks or utilize relay infrastructure for NAT traversal.
Beyond its core replication capabilities, the platform offers comprehensive management tools, including a web-based dashboard for monitoring connection status and throughput, as well as a command-line interface for advanced configuration. It includes robust versioning strategies to protect against data loss and supports complex deployment scenarios through native service integration and observability metrics. The software is designed for cross-platform compatibility and can be installed via standard package managers or containerized environments.