Klip

Secure peer-to-peer clipboard sharing and file transfer across devices on your local network.

🌐 klip-it.app

Klip runs in the system tray and automatically syncs your clipboard between all connected devices. Copy on one machine, paste on another. It also supports sending files directly to a connected peer.

Features

• Clipboard sync — copy text on one device, paste on any other connected device
• File transfer — send files to peers via the system tray menu
• Zero configuration — devices discover each other automatically using mDNS
• End-to-end encryption — all traffic is encrypted with TLS 1.3 using auto-generated certificates
• Cross-platform — works on macOS, Linux, and Windows

How it works

1. On startup, Klip generates a self-signed TLS certificate and advertises itself on the local network via mDNS
2. When another Klip instance is discovered, devices establish a mutual TLS connection and exchange a handshake
3. Clipboard changes are detected and broadcast to all connected peers in real time
4. File transfers use a separate data channel with offer/accept protocol and progress tracking

Klip Pro

The free version supports up to 2 devices. Klip Pro removes this limit.

macOS / Windows

Download the latest release from the Releases page.

macOS Gatekeeper Notice

macOS may block Klip on first launch because it is not signed with an Apple Developer certificate. This is expected for open-source tools distributed outside the App Store.

To open it anyway:

Option 1 — right-click the binary and select Open, then confirm in the dialog.

Option 2 — run this in Terminal after downloading:

xattr -cr /path/to/klip-darwin-arm64

Then double-click as normal.

Windows Defender / Antivirus Notice

Klip is unsigned, so your antivirus may flag it as suspicious. This is a false positive — the app is open source and you can review or build it yourself:

git clone https://github.com/PatrykDz95/Klip
cd Klip
go build -ldflags "-s -w" -o klip.exe ./cmd/klip

Klip appears in your system tray. From there you can:

• See connected devices
• Send a file — click the device name in the tray menu and select a file
• Pause/resume clipboard syncing

Testing

• Unit/integration tests: go test ./... -count=1 -timeout=2m
• Race detector: go test -race ./... -count=1 -timeout=5m
• Coverage report file (local): go test ./... -covermode=atomic -coverprofile=coverage.out

Security

• All connections use TLS 1.3
• Peer identity uses TOFU + certificate fingerprint pinning
• First contact auto-trusts a device; future certificate changes require user confirmation
• Certificates are ECDSA P-256, auto-generated and stored in ~/.klip-sync/certs/
• Trusted peer fingerprints are stored in ~/.klip-sync/trusted_peers.json
• Clipboard data is never sent unencrypted
• File transfers require explicit acceptance from the receiving device