PrismDesk turns an Android phone or tablet into a real second monitor for a Windows 11 PC — over Wi-Fi, or over a cable using USB tethering.

Windows sees a genuine extra display with its own resolution, created by the PrismDesk virtual display driver on the PC. You drag windows onto it like any other monitor. It is not a mirrored window you have to arrange around.

■ YOU ALSO NEED A WINDOWS PC

This app is only the screen. The PrismDesk host application runs on your PC and does the work, and this app can do nothing without it.

• Windows 11, 64-bit, build 22000 or later. Windows 10 is not supported.
• Your PC and your Android device must be on the same local network. There is no cloud relay, and this is not remote access over the internet.

■ HOW IT WORKS

1. Install the PrismDesk host on the PC.
2. Open this app. It finds the PC on your network by itself — or scan the QR code the PC shows, or type the address once.
3. Drag a window onto the new display.

After that, it is waiting for you again when the PC restarts.

■ WHAT IT DOES

• Extend or mirror — run the device as an additional desktop of its own, or as a copy of a screen you already have.
• Pen — pressure, tilt and rotation arrive on the PC as real Windows pen input, so pressure-sensitive apps see a pen and not a mouse.
• Touch and keyboard — taps, drags and typing go back to the PC.
• Audio — sound from the PC plays on the device.
• Pick the resolution, refresh rate, frame rate and video codec (H.264 or H.265), or leave them on automatic.
• Reconnects by itself after Wi-Fi drops out, and picks the session back up where it left off.
• Quick Settings tile and home screen shortcuts for the PCs you use most.
• English and Japanese, following your device language or set by hand.

■ ENCRYPTED BY DEFAULT

TLS 1.3 on the control and input channels, AES-256-GCM on video, audio and camera. The device pins the PC's certificate fingerprint, which it reads from the QR code or the connection string — so it is talking to your PC and not to something else that answered.

■ PRIVACY

• No account and no sign-in.
• No advertising, analytics or tracking SDKs.
• Your screen, audio and input travel directly between your own devices on your own network. They never pass through our servers — we operate none that this app talks to.
• No location, contacts, storage or microphone permissions are requested.
• Diagnostics are written to your own device, and are shared only if you choose to send them.

■ ABOUT THE CAMERA PERMISSION

The camera is used for two things, and only when you ask for them: reading the connection QR code the PC displays, and — if you turn the feature on — sending the device camera to the PC, where it appears as a webcam you can pick in a video call. QR codes are decoded on the device.

■ EDITIONS

The free edition covers the basics: one device at a time, SDR, pen and touch input, and audio.

PrismDesk Pro is an edition of the Windows host application. It adds HDR10, up to four devices connected at once, and using the device camera as a Windows webcam. This app is the same app either way — it shows what the PC allows.

■ GOOD TO KNOW BEFORE YOU INSTALL

• It works on your own network only. Away from your PC, it does nothing.
• Frame rate follows what Windows and your PC's encoder can deliver for what is on screen; we do not advertise a number.
• On some large-screen devices Android ignores an app's request to rotate the panel. If your tablet will not turn, that setting belongs to the device, not to PrismDesk.

Questions: support@prismdesk.app