C3Sync documentation

C3Sync synchronizes AI coding-agent sessions and the working-tree state attached to them across machines you own. Payloads are end-to-end encrypted before reaching a self-hosted NATS JetStream hub.

WARNING — > C3Sync is beta software. Linux is the supported beta platform. Back up important work and read the security model before relying on it.

What C3Sync carries

Native session data for Claude Code, Codex, OpenCode, and Pi
Tracked and untracked working-tree files, with .gitignore honored
Restore anchors that pair agent turns with file state
Durable encrypted events that offline peers replay later

Get the beta

The current public release is C3Sync 1.0.0-beta.25. It includes archives and direct binaries for Linux x64/ARM64, macOS Intel/Apple Silicon, and Windows x64/ARM64, plus a checksum manifest. Linux remains the supported beta platform; macOS and Windows are previews pending physical qualification.

C3 Desktop can download and verify the matching C3Sync runtime during setup. The standalone installers also verify the selected archive before installing:

curl -fsSL https://getc3.app/sync/install.sh | bash -s -- --beta

powershell

$env:C3SYNC_CHANNEL='beta'; irm https://getc3.app/sync/install.ps1 | iex

Start here

Follow the quickstart.
Understand sync and merge behavior.
Review safety and conflicts.
Read the complete security model.