Synergy + Parsec · Local-first · No cloud

One keyboard and mouse for every computer on your desk.

Glide your cursor across screen edges to control the next machine — keyboard, mouse, clipboard and files follow. And when you need a machine's actual screen, remote-desktop into it and take over in real time. All peer-to-peer over your LAN, on Windows, macOS and Linux.

Download $5/mo · $50/yr
Windows · macOS · Linux
TLS 1.3 peer-to-peer No account required Cross-platform
§ 01 — how it works

Two ways to reach across machines.

input sharing + remote desktop
one app, all local
Input sharing · for screens side by side

Glide across

Push your cursor off the edge of one screen and you're instantly on the next machine. One keyboard and mouse drive them all, arranged on a multi-monitor canvas you drag to match your real desk — and the clipboard and files come with you.

→Best when your machines sit side by side and you want them to feel like one continuous desktop.
Remote desktop · for a machine in another room

Stream in

When you need a machine's actual display — a headless box, a PC in the next room — remote-desktop straight in and view and control its full screen in real time, low-latency, over your LAN. No cursor-crossing required.

→Best when the machine is out of reach or has no monitor and you need its real screen, not just its input.
§ 02 — what's in the box

Everything your desk shares, in one app.

core capabilities first
supporting features below
01

Seamless keyboard & mouse sharing

One keyboard and one mouse drive every computer on your desk. Slide off a screen edge and your input lands on the next machine instantly — no switch, no KVM, no perceptible lag.

02

Multi-monitor canvas layout

Drag each machine's screens onto a real layout canvas to match your desk — zoom, pan, edge-snapping and L-shaped setups. The cursor crosses exactly where your monitors actually meet.

03

Remote desktop — view & control any screen

Need a machine's actual display? Remote-desktop into a headless box or a PC in another room and take over its full screen in real time — its audio comes along, low-latency, peer-to-peer, never leaving your LAN. Beta builds stream with Iapetus, our own built-from-scratch video codec — pixel-perfect 4:4:4 color with no third-party codec dependencies.

04

Shared clipboard + file transfer

Copy on one machine, paste on another. Send a file to any connected computer, or drag it across the edge and drop it straight onto that machine — with a live progress card (speed, ETA, cancel) on both ends. Your clipboard follows you everywhere — and an optional clipboard history keeps recent copies one click away, held in memory only, never written to disk, never shared, and off until you turn it on.

…and more

Controller sharing

Forward a controller to another PC as a virtual Xbox pad, with multi-pad routing.

Pen / tabletbeta

Forward a drawing tablet with full pressure and tilt across the LAN, driver-free.

Works at the lock screen

Keyboard and mouse keep working at the lock and login screen.

Automatic updates

Signed updates roll out and verify in the background. You stay current, hands-off.

Audio passthrough

Hear a connected computer's sound on this one — automatically while you view its screen, or pick it as a source any time. Optionally forward one computer's audio to another, and choose exactly which microphone or input to capture and which speakers to play it on.

Webcam sharingbeta

Share a camera to your other computers and view it from another machine — with an "on air" light on the owner whenever its camera is being watched. Opt-in per device.

Remote Sessions

Save SSH connection profiles and open a full terminal to any server right inside the app — your machines and your remote boxes in one place. Optionally pull your SSH logins straight from 1Password (via the 1Password CLI); Promethean Link stores references only, never your secrets.

Privacy mode

Working on a machine remotely? Blank its physical screens and mute its speakers so nobody at the desk can watch or listen — one toggle, off the moment you're done.

Watch from a browserbeta

Open a shared screen in any browser on your LAN — no install needed on the viewing machine. Handy for a laptop, a spare tablet, or a quick look from anywhere in the house.

Pixel-perfect alignmentbeta

A Calibrate panel plus an on-screen alignment overlay line your monitors up to the pixel — drag the alignment lines right on your monitors, from either machine, until the cursor crosses exactly level. Adjustable line density and thickness, a darkened backdrop so the lines pop, and it's all remembered.

§ 03 — see it in action

30 seconds to get it.

§ 04 — by design

Your desk, your network — and nothing in between.

Promethean Link never routes your input, screens, clipboard or files through anyone else's servers. Machines find each other on your LAN and talk directly, encrypted end to end. The only outbound request is a small license check that carries no user data.

  • LAN-only, peer-to-peerDirect device-to-device connections on your local network. No relay, no middleman hop.
  • TLS 1.3, per-link keysEvery connection is encrypted with its own keys. Pair once; nothing travels in the clear.
  • No cloud, no accountThere's no sign-up and no cloud service to depend on. It works fully offline, on your own wire.
  • You approve every first connectionA new computer must be confirmed with a short pairing code — and you choose per machine: remember it for automatic reconnects, or require a fresh code every time.
§ 05 — platform support

The spec sheet, nothing hidden.

Windows / macOS / Linux · X11 · Wayland not yet supported
Android phone client in beta · iOS planned, not built
Capability support by operating system. Full support, partial or beta, planned, not possible, or not applicable. Android and iOS are phone clients, not full computers, so several rows do not apply to them.
capabilityFeature Windowscol 01 macOScol 02 Linuxx11 · col 03 Android17beta · col 04 iOS18planned · col 05
Keyboard & mouse sharing1core ✓ ✓ ◐ n/a n/a
Multi-monitor layout canvascore ✓ ✓ ✓ n/a n/a
Alignment overlay & pixel calibration15core · calibrate ✓ ✓ ◐ n/a n/a
Shared clipboard2core ✓ ✓ ◐ ◐ —
File transfer3core ✓ ✓ ◐ ◐ —
Remote desktop — view another PC11remote ✓ ✓ ◐ ◐ —
Remote desktop — be viewed & controlled4remote ✓ ✓ ◐ n/a n/a
Audio passthrough12remote · device pick ✓ ✓ ◐ ◐ —
Webcam sharing13remote · on-air ◐ ◐ ◐ n/a n/a
Privacy mode — blank & mute while viewed16remote · privacy ✓ ✓ ◐ n/a n/a
Game controller sharing5supporting ✓ ◐ ◐ n/a n/a
Gaming keypad detection (Tartarus etc.)6supporting ◐ — ◐ n/a n/a
Remote Sessions (SSH + terminal)14supporting ✓ ✓ ✓ — —
Pen / drawing tablet7supporting ◐ — ◐ n/a n/a
Works at the lock / login screen8system ✓ ◐ — n/a n/a
Automatic updates9system ✓ ✓ ◐ — —
Display server10system Windows macOS X11 only Android 9+ —
✓ Full ◐ Partial / Beta — Planned ✗ Not possible n/a Doesn't apply to a phone
  • 1Linux now sends & receives with correct key mapping and suppresses local input in edge-crossing mode via an X11 grab (the cursor isn't hidden during capture yet).
  • 2Text and images sync on all three platforms (macOS image sync now shipped). An optional local clipboard history (off by default) keeps recent copies in memory only — never written to disk, never shared to other computers. On Windows and macOS it skips content apps mark as confidential (e.g. password managers); Linux apps don't reliably mark secrets, so be mindful there.
  • 3Sending a file works cross-platform on all three, in every direction — verified between Windows and macOS. Dragging a file across the screen edge onto another computer also works on all three. Where it lands differs: on Windows it goes into the exact Explorer folder or desktop under your cursor; on macOS and Linux, dropping on the desktop puts it there, and dropping anywhere else puts it in that computer’s chosen receive folder. The transfer card always shows the real destination. Starting a drag out of a machine is Windows-only for now — macOS and Linux receive drops but cannot yet begin one.
  • 4Windows, macOS and Linux can all be viewed & controlled; Linux includes headless hosts. macOS hosting needs macOS 12.3+ with Screen Recording permission granted once. Linux hosting is newer and still in beta.
  • 5Linux now shares its own controller and receives a forwarded one — both ways (beta, not yet hardware-verified). macOS can share its own controller to another machine (beta); receiving a forwarded controller on the Mac isn't possible yet (no virtual-pad driver).
  • 6Detected & listed; forwards on the keyboard stream.
  • 7Beta on Windows & Linux (uinput); both still want real-tablet validation.
  • 8Windows: full — keyboard and mouse keep working at the lock and login screen. macOS: a login-window agent can now inject your forwarded keyboard/mouse at the login screen (new, beta) — no screen capture there, and never the FileVault pre-boot unlock, which macOS isolates.
  • 9Windows and macOS both update fully in-app: download, verify, replace, relaunch. On macOS the update is checked against Apple’s notarization before anything is replaced, and the previous version is kept until the new one is safely in place. Linux checks in-app and installs via the .deb (apt) or a portable AppImage.
  • 10Linux is X11 only; Wayland isn't supported yet.
  • 11macOS views a remote host with a native hardware-decoded viewer (VideoToolbox). Linux (FFmpeg decoder + X11 viewer window) also views a remote host — newer and still in beta.
  • 12Hear a connected computer's system sound — automatically while you view its screen, or pick it as a source to keep hearing it without viewing. You can also forward one computer's audio to another, and choose which capture device feeds it and which output device plays it. Windows (WASAPI loopback + playback) and macOS (system mix or a chosen microphone/input, playback on a chosen output) are both full, with input/output device selection; Linux carries it over PulseAudio with device selection (beta).
  • 13Share a camera to other computers and view it from another machine, with an "on air" indicator on the owner while a camera is being watched. In-app (viewable inside Promethean Link) on all three platforms — new and in beta; showing the shared camera as a virtual webcam inside other apps (Zoom, OBS, Discord) is not shipped yet.
  • 14Saved SSH connection profiles with an in-app terminal, on Windows, macOS and Linux. Optional 1Password integration (beta) fills SSH logins from your vaults via the 1Password CLI where it's installed — Promethean Link keeps references only and never stores your secrets.
  • 15Line monitors up to the pixel: an in-app Calibrate panel with 1 px nudges per computer (all three platforms), plus an on-monitor alignment overlay where you drag the gold edge lines and green helper lines directly on the screens — from either machine — with adjustable line density and thickness and a darkened backdrop. The overlay is proven on Windows and macOS; on Linux it is still beta and needs X11 (not Wayland). Calibrated positions persist across restarts.
  • 16While you view a machine remotely, blank its physical displays and mute its speakers so no one at its desk can watch or listen — from the viewer's toolbar, or automatically whenever it's being viewed (Settings). Windows and macOS are full; Linux blanks via DPMS on X11 and mutes via PulseAudio (on Wayland, audio mute only).
  • 17Android is a phone client, not a fourth computer. It views and controls a computer you've paired it with; it never shares its own screen, is never controlled by a computer, and isn't part of the edge-crossing layout — which is why most rows above read n/a rather than "not yet". What it does do is listed in the phone table below. It needs Android 9 or later on a 64-bit (arm64) phone. The app is in beta and is not on the Google Play Store; there is no public download yet.
  • 18iOS is planned and not built. No iOS app exists today — not in beta, not in TestFlight, not on the App Store. The groundwork on our side (app icons and the website's Universal Links association file) is in place, but the app itself hasn't been built, so every iOS cell reads "planned".
§ 05b — the phone app

On your phone.

The phone app is a client: it reaches into a computer you've paired it with — screen, mouse, keyboard, clipboard, files and sound — as if you were sitting at it. It is not a fourth machine on the layout canvas. It doesn't share its own screen, it can't be controlled from a computer, and it views one computer at a time. Here is exactly what it does today.

Availability

Android — beta, and you can't download it yet. The app is real and runs on real hardware, but it is not published to the Google Play Store and there is no public download link, so there is nothing here for you to click. When it's ready to hand out, it'll appear on this page. Coming soon.

iOS — planned, not built. There is no iPhone or iPad app yet, in any form.

What the Promethean Link phone app does, on Android and iOS.
phone clientWhat it does Androidbeta iOSplanned
Pair with a computerapair ✓ —
View a computer's screenbview ◐ —
Touch control — trackpad & direct touchccontrol ✓ —
Keyboard, with modifier keysdcontrol ◐ —
Switch between the computer's monitorsview ✓ —
Clipboard, both directionsesync ◐ —
Send & receive filesfsync ◐ —
Hear the computer's soundgaudio ✓ —
Ask the computer to blank its screenhprivacy ◐ —
Groups, and forgetting a computerimanage ◐ —
SSH terminal on the phonejplanned — —
Share the phone's own screen, or be controlled from a computerby design ✗ ✗
✓ Full ◐ Partial / Beta — Planned ✗ Not offered
  • aScan the pairing QR code a computer shows you — either with the app's own scanner, or with the phone's ordinary camera app, which hands off to Promethean Link. If the camera isn't an option, you can type the computer's address in by hand instead. Both screens then show the same six-digit code for you to compare before trust is granted; it's a check, never something you type in.
  • bWatching a computer's screen from the phone is new and still in beta. The phone decodes Promethean Link's own video format only — it will report a stream as unavailable rather than fall back to another codec. We have not published frame-rate, latency or battery figures because we have not measured them, so we're not claiming any.
  • cTwo touch modes: trackpad, where you slide anywhere to move the pointer (long-press to lock a drag), and direct touch, where you tap the thing you want (long-press for right-click). Two fingers scroll. Pinch zooms your own view of the screen — it stays on the phone and is never sent to the computer.
  • dA full keyboard with a modifier bar: Ctrl, Alt, Shift, Cmd/Win stick until you use them, plus Esc, Tab and arrows. The labels follow the computer you're on (Opt/Cmd for a Mac, Alt/Win for a PC), but the phone deliberately does not remap Ctrl to Cmd for you — the key you press is the key that arrives.
  • eText only, both ways. Computer → phone is automatic. Phone → computer is automatic only while the app is on screen and in front — Android forbids apps from reading the clipboard in the background, and we don't try to work around that. There's a "Send clipboard now" button for when you want it explicitly. Images sent to the phone are dropped rather than pasted.
  • fBoth directions: pick a file to send to the computer, and receive files from it into a folder you choose (or be asked each time, then save or share it on). Two caveats worth knowing: one send per computer at a time, and files offered to the phone are accepted automatically — there's no accept/decline prompt yet.
  • gHear the sound of the computer you're viewing, on the phone. One direction only — the phone's microphone is never captured or sent anywhere.
  • hThis asks the computer to blank its screen while you're working on it remotely. It is a request: the computer doesn't report back, so the phone shows it as "requested", not as confirmed. Treat it as a courtesy, not a security control.
  • iSort your computers into groups on the phone — those groups live on the phone and aren't shared back to your computers. "Forget" removes the phone's half of the pairing; trust is two-sided, so forget the phone on the computer too if you want it gone from both.
  • jPlanned. The phone can store and organise your SSH hosts, but there is no terminal on the phone yet — it cannot open an SSH session. The in-app terminal exists on Windows, macOS and Linux only.
§ 06 — pricing

Simple, honest pricing.

All features, up to 5 computers. Subscribe monthly or yearly — or pay once for a lifetime license. No accounts, no cloud.

30-day money-back guarantee — no questions asked

Monthly

$5 /mo

billed monthly

  • Up to 5 computers
  • All features included
  • 30-day money-back guarantee
  • Cancel anytime
Launching soon
Save $10 · 2 months free

Annual

$50 /yr

billed once a year

  • Up to 5 computers
  • All features included
  • 30-day money-back guarantee
  • Cancel anytime
Launching soon

Lifetime

$250 once

pay once, yours forever

  • Up to 5 computers
  • All features included
  • Never expires — no subscription
  • 30-day money-back guarantee
Launching soon

Limited-time offer — the lifetime price may rise or be discontinued at any time. Lock it in while it lasts.

Checkout opens with the public launch — the beta is downloadable today from GitHub below. No free trial — but the 30-day money-back guarantee means zero risk. If it's not for you, we refund you, no questions asked. The lifetime price is offered for a limited time and may change or be withdrawn.

§ 07 — download

Get it running.

Windows is the most complete platform today, with a ready-to-run installer. Linux ships a prebuilt .deb and a portable AppImage (X11, beta). macOS ships a prebuilt .dmg (Apple Silicon or Intel), signed with our Apple Developer ID and notarized by Apple — it installs by drag-and-drop with no security prompt. macOS and Linux are newer than Windows; expect some rough edges while they catch up. There are two release channels: stable, and a faster-moving beta where the newest features (Iapetus streaming, the alignment overlay, and more) land first — switch channels any time in Settings → Updates.

The Android phone client is real and in beta, but it is not on the Google Play Store and there's no public download yet — the button below is desktop only. iOS hasn't been built at all. Both are covered honestly in the platform matrix.

Download from GitHub

Windows

Installer · Windows 10 22H2+ · x64

READY

macOS

.dmg · macOS 12+ · Apple Silicon/Intel — beta

BETA

Linux

.deb & AppImage · X11 · x64 — beta

BETA

Android — phone client

Beta · not on Google Play · no download yet

SOON

iOS — phone client

Planned · no build exists yet

PLANNED

Minimum requirements

  • Local area network (Ethernet or Wi-Fi) — everything stays on your LAN
  • Windows 10 version 22H2 (build 19045) or later, x64, for the prebuilt installer
  • DirectX 11-capable GPU for remote-desktop decode
  • A Promethean Link license key to activate
  • Linux: a prebuilt .deb (Debian/Ubuntu) or portable AppImage, X11, x64 — beta
  • macOS 12 Monterey or later (Apple Silicon or Intel); the .dmg is Developer ID-signed and notarized — beta
  • Phone client (view & control a computer): Android 9 or later, 64-bit arm64 — beta, and not publicly downloadable yet. No iOS build exists.
§ 08 — questions

Common questions.

General

One keyboard, mouse, clipboard, and screen across every computer on your desk, all on your local network. Glide your cursor off a screen edge to control the next machine (like Synergy), and remote-desktop into any machine when you need its screen (like Parsec) — one app, no cloud, no account.
Up to 5 computers; all features are included for all 5.
No free trial, but every plan has a 30-day money-back guarantee — refund within 30 days, no questions asked.
No. Input, clipboard, files, and the remote-desktop stream stay on your LAN (peer-to-peer, TLS-encrypted). The only outbound request is a small license check carrying no user data.
No. The first time a computer connects you confirm a short pairing code, and you decide per machine: remember it so it reconnects automatically from then on, or require a fresh code every single time it connects. Every link is TLS-encrypted with its own keys either way.
Cross-platform: Windows, macOS, and Linux. Windows is the most complete today, and macOS is close behind — keyboard/mouse sharing, the layout canvas, clipboard, remote desktop (viewing and being viewed), and audio are all full on the Mac. Linux covers the same ground but is newer and still in beta on several of those. There's also an Android phone client in beta — see the next question. See the capability matrix above for exactly what works where.
On Android, yes — in beta, but you can't get it yet. It isn't published to the Google Play Store and there's no public download link, so there's nothing for us to point you at right now; it's coming. On iOS there is no app at all yet — not in beta, not in TestFlight. It's planned, not built. The Android app is a client: it views and controls a computer you've paired it with (screen, touch and keyboard control, clipboard, files, sound), but it never shares the phone's own screen and can't be controlled from a computer. The phone table in the platform matrix lists exactly what it does and where it's partial.
You get a license key; paste it in Settings. Activation is instant and works offline after the first check.
Yes, from the customer portal; you keep access through the end of your billing period.

Troubleshooting

Turn Discovery on (both machines), ensure they're on the same local network, and allow Promethean Link through the firewall: TCP 24800 and UDP 24801 on the Private network profile.
In the layout canvas, arrange the machines so their screens share an edge, and confirm both are connected. ScrollLock locks the cursor to the current screen — press it again to unlock.
Install/repair the ViGEmBus driver on the receiving PC (reinstalling Promethean Link includes it), and pick the destination in the Controllers panel. The physical controller stays active on the sharing PC.
The viewing PC needs a DirectX 11-capable GPU and the machine being viewed must allow it; reconnect from Connections → View screen.
Grant Promethean Link both Accessibility and Input Monitoring under System Settings → Privacy & Security, then relaunch.
Not yet — today Promethean Link uses X11, so log into an "Xorg"/"X11" session for now. Wayland support is on the roadmap, built on the modern desktop-portal APIs (PipeWire, RemoteDesktop/InputCapture portals, libei) — the same approach Deskflow and GNOME Remote Desktop use. Remote-desktop and being-controlled will come first and work broadly; the cursor-crosses-the-edge input capture depends on your desktop (GNOME and KDE expose the needed portal; some others don't yet).
Recent versions reopen on their own; if an older one didn't, open it once by hand — updates from then on relaunch automatically.