Two computers on one desk. Two keyboards, two mice, two sets of muscle memory. A software KVM turns your primary mouse and keyboard into a hive input: slide the cursor to the edge of one screen and it appears on the next machine, ready to type. The seven picks below cover Windows, macOS, and Linux, free and paid, and they all skip the hardware KVM box.
What to look for in a software KVM
Not every pick fits every setup. Weigh these:
- Encrypted link. Keystrokes cross a local network. TLS or SSH tunneling matters if the LAN is not fully trusted.
- Shared clipboard. Copy on one machine, paste on the other. A must for real productivity.
- File drag-and-drop. Some tools support cross-machine file drops; others copy through clipboard only.
- Latency. Sub-frame latency separates a KVM you can gam on from one you can only text on.
- Cross-OS coverage. Mixing Windows, macOS, and Linux in one setup narrows the options fast.
Quick comparison
| App | Best for | Platforms | Free | TLS | Clipboard sync |
|---|---|---|---|---|---|
| Deskflow | Cross-platform open source | Windows, macOS, Linux | Yes | Yes | Yes |
| Barrier | Barrier legacy setups | Windows, macOS, Linux | Yes | Optional | Yes |
| Synergy | Paid polish and support | Windows, macOS, Linux | Trial | Yes | Yes |
| Mouse Without Borders | Windows-only free pick | Windows | Yes | Yes | Yes |
| Input Director | Windows-only with granular rules | Windows | Free (home) | Yes | Yes |
| ShareMouse | Windows and macOS paired | Windows, macOS | Free (2 PCs) | Yes | Yes |
| Multiplicity | Stardock ecosystem | Windows | Trial | Yes | Yes |
1. Deskflow, best open-source cross-platform pick
Deskflow is the community fork that took over from Barrier when Barrier stalled. It runs on Windows, macOS, and Linux, links machines through an encrypted TLS connection, and syncs the clipboard both ways. Configuration is a drag-and-drop grid of screens.
The reason to pick it is that it is the only actively maintained free tool that covers all three OSes and does what a paid KVM does.
Where it falls short: Setup on Wayland Linux is still rough because Wayland’s security model complicates global input injection. X11 works fine.
Pricing: Free and open source (GPLv2).
Platforms: Windows, macOS, Linux.
Download: deskflow.org · GitHub
Bottom line: The default pick in 2026 for a free cross-platform software KVM.
2. Barrier, best if you already run it
Barrier is the older Synergy fork that Deskflow succeeded. Development has slowed to a crawl, but the last releases still work fine on current OSes and are what many older tutorials assume.
If your setup already runs Barrier and everything works, there is no reason to migrate to Deskflow. If you are starting fresh, install Deskflow instead.
Where it falls short: Not actively maintained. TLS is optional and not on by default in older configs.
Pricing: Free and open source (GPLv2).
Platforms: Windows, macOS, Linux.
Download: GitHub
Bottom line: Fine if you already run it. Otherwise Deskflow is the current pick.
3. Synergy, best paid pick with support
Synergy is the original commercial software KVM and the parent of both Barrier and Deskflow. Symless offers licensed builds with polished setup wizards, TLS by default, and paid support. Synergy 3 is the current generation.
The reason to pay is a smoother onboarding and someone to write to when something breaks. Feature parity with Deskflow is close.
Where it falls short: Not free. If you can handle Deskflow’s config, you get 95% of the value.
Pricing: One-time license (Basic and Pro tiers). Free trial.
Platforms: Windows, macOS, Linux.
Download: symless.com/synergy
Bottom line: The pick when you would rather pay than tinker.
4. Mouse Without Borders, best free Windows-only pick
Microsoft’s Mouse Without Borders links up to four Windows PCs on the same LAN with a shared mouse, keyboard, and clipboard. It supports drag-and-drop file transfer and screenshot copy across machines.
Now bundled inside PowerToys as of PowerToys 0.73, it is a one-click enable if you already run PowerToys.
Where it falls short: Windows only. No macOS or Linux endpoint.
Pricing: Free (MIT).
Platforms: Windows 10, Windows 11.
Download: Microsoft Store (PowerToys) · GitHub
Bottom line: The default on a Windows-only desk.
5. Input Director, best granular Windows rules
Input Director is an older Windows-only tool with the deepest per-machine rules of anything here. Different keyboard layouts per machine, per-monitor cursor transitions, hotkey-triggered switching, and a hidden “master control” mode all live in a single dense configuration UI.
Home use is free. Commercial use requires a license.
Where it falls short: Interface is dated. Windows only.
Pricing: Free for personal use. Commercial license required otherwise.
Platforms: Windows.
Download: inputdirector.com
Bottom line: The pick when you need very specific per-machine rules on Windows.
6. ShareMouse, best light paid pick for Windows and macOS
ShareMouse links Windows and macOS machines with a small footprint installer and one config screen. The free tier covers two machines, which is enough for most home desks. Paid unlocks more machines and drag-and-drop file transfer.
Its selling point over Deskflow is a smoother macOS install and a paid-support option.
Where it falls short: No Linux support. The free tier is limited to two machines and non-commercial use.
Pricing: Free for two machines and personal use. Paid tiers unlock more machines and commercial use.
Platforms: Windows, macOS.
Download: sharemouse.com
Bottom line: The pick when Windows and macOS are your two machines and you want a very simple installer.
7. Multiplicity, best inside a Stardock setup
Multiplicity by Stardock links up to nine Windows PCs on one desk with drag-and-drop, clipboard sync, and per-machine sound routing. It integrates with the rest of Stardock’s ecosystem (Fences, WindowFX) if you already use those.
The reason to pick it over Mouse Without Borders is scale (nine machines vs four) and Stardock’s paid support model.
Where it falls short: Paid only after trial. Windows only.
Pricing: One-time license per tier (KM, Pro).
Platforms: Windows.
Download: stardock.com/products/multiplicity
Bottom line: The pick when you run four or more Windows machines and paid is fine.
How to pick
- Cross-platform free: Deskflow.
- Windows only, free: Mouse Without Borders (via PowerToys).
- Windows only, granular rules: Input Director.
- Windows + macOS, easy install: ShareMouse.
- Prefer paid support: Synergy or Multiplicity.
- Already run Barrier: stay on Barrier or migrate to Deskflow.
FAQ
Do these tools work over Wi-Fi?
Yes, all seven work over any TCP link on the same LAN, wired or wireless. Wired is more consistent for latency; Wi-Fi is fine for typing and browsing but can feel laggy for fast pointing.
Are keystrokes encrypted between machines?
Deskflow, Synergy, ShareMouse, Input Director, and Multiplicity enable TLS by default. Mouse Without Borders encrypts by default. Barrier’s TLS is optional and not always on.
Can I share the clipboard between Mac and Windows?
Yes. Deskflow, Synergy, and ShareMouse all sync text and image clipboards cross-OS. File drag-and-drop is more limited across OSes.
Is there a hardware alternative worth considering?
Yes. A USB hardware KVM avoids installing anything and works before login, but you lose the shared clipboard and drag-and-drop. Software KVMs win once those features matter.
Does this work through a VPN or over the internet?
Yes, if you can route the machines onto a shared virtual network (Tailscale, ZeroTier, WireGuard). Latency across the internet is generally too high for fast pointing.
