Syncthing Relay

Public relay to help file synchronization between Syncthing devices when direct peer-to-peer connection is not possible.

Syncthing Relay acts as a relay point for Syncthing devices that cannot always reach each other directly, for example because of NAT, a firewall or a restrictive network context. The service then allows synchronization traffic to pass through a relay, without turning Syncthing into centralized cloud storage.

It is mainly a useful component for people who already use Syncthing and want to improve the reliability of exchanges between mobile, remote or poorly exposed devices. In other words, it is not a storage service by itself, but a piece of infrastructure that helps an existing decentralized setup work more consistently in the real world.

Service URL	syncthing.hostux.net
Service type	Public relay for Syncthing synchronization
Free software used	Syncthing Relay Server
Project website	syncthing.net
Source code	github.com/syncthing/relaysrv
Account required	No

• Improve connectivity between devices when direct peer-to-peer connection fails.
• Keep a decentralized model without going through central storage.
• Help synchronization between devices behind NAT, firewalls or restrictive networks.
• Make an existing Syncthing setup more robust, especially for mobile use.
• Use a public relay without having to deploy your own server immediately.

• Relay endpoint for Syncthing connections.
• Usable with standard Syncthing clients.
• No web interface for files and no persistent storage.
• Complements direct peer-to-peer connections rather than replacing them.

This distinction matters: using a relay keeps the general Syncthing model intact. Your devices still synchronize with each other; they just have more ways to reach one another when the network gets in the way.

• Syncthing always prefers a direct connection between devices when one is possible.
• The relay is only used as a fallback when two devices cannot communicate directly.
• If a direct connection becomes possible again, Syncthing stops using the relay and returns to peer-to-peer mode.
• The relay does not store your files: it only forwards encrypted data between the devices involved.
• Using a relay is generally slower than a direct connection.

• Data exchanged through the relay remains end-to-end encrypted between Syncthing devices.
• The relay cannot inspect the content of transmitted files.
• However, a relay does see some metadata required for operation, especially device IDs and IP addresses used for the connection.
• The relay operator can also see the volume of traffic passing through the service.
• A public relay improves connectivity, but it does not replace proper network configuration or a direct connection when one is possible.

• Synchronize files between devices behind NAT or strict firewalls.
• Improve continuity of an existing Syncthing setup between several sites or Internet connections.
• Make synchronization easier for mobile, roaming or rarely co-located devices.
• Support Syncthing usage without depending on a centralized storage service.

Service: syncthing.hostux.net