Syncthing is an open-source continuous file synchronization program written in Go that keeps files identical across two or more computers, aimed at individual users who want to sync their own data without a third-party service.

What it is

Syncthing is a continuous file synchronization program that synchronizes files between two or more computers. It is written in Go, licensed under the MPLv2 License, and communicates over its own peer-to-peer protocol, documented as bep-v1 on the project's documentation site. It runs as a background daemon, offers GUI implementations for Windows, Mac, and Linux, and can be built from source with a single command.

The concrete problem Syncthing solves is keeping copies of a person's files consistent across machines without routing them through someone else's storage. Its stated goals put safety from data loss first and security against attackers second: it takes precautions against corrupting files and against allowing data to be susceptible to eavesdropping or modification by unauthorized parties, while remaining easy to use, automatic, and universally available on every common computer. It sits in the Productivity & Utilities category under File Management & Sync, as a peer-to-peer alternative to hosted sync-and-share services.

Key capabilities

• Synchronizes files continuously between two or more computers, with user interaction required only when absolutely necessary.
• Operates peer-to-peer, with no central server implied in its design; the project's topics include p2p and peer-to-peer.
• Exchanges data over the documented Block Exchange Protocol, bep-v1.
• Ships GPG-signed release binaries, with keys published at https://syncthing.net/security/, plus code-signed macOS and Windows binaries.
• Includes a built-in automatic upgrade mechanism (disabled in some distribution channels) that verifies updates using a compiled-in ECDSA signature.
• Provides examples for keeping Syncthing running in the background on your system in the etc directory of the repository.
• Builds from source by running go run build.go, which places the binaries in ./bin.

Who uses it and how

• Individual users syncing their own files between personal computers, which matches the project's explicit goal that Syncthing is primarily about empowering the individual user.
• People running it as a background service on Windows, Mac, or Linux, using the examples in the etc directory, alongside one of the several GUI wrappers listed in the documentation.
• Users deploying it in Docker, following the dedicated README-Docker.md in the repository.
• Contributors and self-builders who compile from a release bundle or a git checkout with go run build.go, and who report bugs in the GitHub issue tracker or discuss usage on the Syncthing Forum.
• Anyone who needs assurance about binary provenance, checking GPG signatures against the published key before installing.

Getting started

Follow the getting started guide on the documentation site, run Syncthing in Docker by consulting README-Docker.md, or build it from source with go run build.go to produce binaries in ./bin.

How it compares

This registry entry provides no list of paid products that Syncthing replaces, and the project's own facts name no comparable tools alongside it, so Syncthing stands alone in this registry.

When to use it — and when not

Because it is peer-to-peer and has no hosted option in its own facts, a self-hoster must run and supervise the daemon themselves on each machine and handle background execution via the etc directory examples or Docker. It is explicitly oriented toward individuals rather than organizations, so teams looking for administration, sharing policies, or vendor support should look elsewhere; note also the 388 open issues, which suggest an active but not perfectly tidy backlog.