Vidyut

Copy a screenshot or some text on your Linux laptop, paste it on your Android phone a second later. Or the other way around. Same WiFi. Nothing leaves the LAN.

Vidyut keeps one clipboard pool between those two devices. The newest copy wins. There is no history.

The idea is the same as Universal Clipboard. Android forbids background clipboard reads, so the phone publishes on purpose through the share sheet, screenshot auto-push, or a notification action. Incoming payloads can land with zero taps once clipboard permission is granted.

Files are a separate path. You send them on purpose. Interrupted transfers resume from receiver-confirmed progress, and complete files are checked with SHA-256 before they become visible.

The laptop runs a compiled Bun Relay. It watches the Wayland clipboard, holds the current encrypted payload, advertises _vidyut._tcp over mDNS, and talks to the phone over a LAN WebSocket. Pairing is a QR in the desktop shell, or a one-line host, port, and secret. The phone is the Flutter app in app/. It stays connected through a foreground service so Android does not kill it the moment you switch apps.

Every clipboard payload and file chunk is end-to-end encrypted with the pairing secret. Other devices on the WiFi cannot read it. The relay never sees plaintext.

Guides

• docs/SETUP.md. First pairing, laptop and phone, about five minutes.
• docs/USAGE.md. Daily copy, paste, screenshots, and file sending.
• docs/INSTALL.md. .rpm/.deb, systemd user service, desktop shell, and file-manager actions.
• docs/TROUBLESHOOTING.md. Field-verified fixes.
• CONTEXT.md. Words used in the code and the docs.

The rest of this file is how to build the Relay from source. Most laptops should use the package instead.

Linux packages

Install the .rpm or .deb from GitHub Releases. The package depends on wl-clipboard and ImageMagick. It installs the Relay, the desktop shell, the systemd user unit, and Send with Vidyut for Dolphin and Nautilus. It does not need Bun at runtime.

sudo dnf install ./vidyut-*.rpm      # Fedora
sudo apt install ./vidyut_*.deb      # Debian/Ubuntu

Open the Vidyut desktop shell and scan the pairing QR there. journalctl --user -u vidyut-relay is the fallback.

A newer GitHub release is installed with dnf or apt. There is no auto-update. Open releases in the desktop shell is a GitHub link. It does not download binaries.

Build packages from this tree with bun run build:relay, bun run build:shell, then bash scripts/build-linux-packages.sh (nfpm.yaml).

Relay prerequisites

• A Linux Wayland session. X11 and headless are not supported.
• wl-clipboard 2.3 or newer, so wl-copy and wl-paste exist. 2.3 added ext-data-control-v1, which KDE/KWin needs.
• ImageMagick is recommended. Phone screenshots often arrive as JPEG, and most Linux apps only paste PNG. The relay re-encodes when magick is present.
• Bun 1.3.3 to build and test. The installed binary does not need Bun at runtime.

Run the relay

bun install
bun run build:relay
./dist/vidyut-relay --log-level info

On first run the Relay creates ~/.config/vidyut/relay.json with a persistent pairing secret. Open the desktop shell for the pairing QR. The process also prints a QR and the manual fallback:

host=<lan-ip> port=17321 secret=<pairing-secret>

The secret does not rotate across restarts. Pair once.

The relay refuses to start if the configured port is already in use. It also advertises _vidyut._tcp over mDNS so the phone can find it without typing a host.

Install as a service

bun run install:relay

That compiles dist/vidyut-relay, installs it to ~/.local/bin/, enables the systemd --user unit, and starts it with your graphical session. It also installs Send with Vidyut for Dolphin and Nautilus. If you have already run bun run build:shell, it installs the Tauri desktop shell and autostart entry. The shell is a window and tray around http://127.0.0.1:17321/. It is not the Relay.

See docs/INSTALL.md for the .rpm/.deb path, pairing in the desktop shell, firewall notes, and service commands.

Android app

The Flutter app lives in app/. From there:

flutter pub get
flutter analyze
flutter test
flutter build apk --debug

CI pins Flutter 3.44.4 on the stable channel. Details are in app/README.md.

Development checks

bun run typecheck
bun test
bun run build:relay
bun run build:shell