10 Best Synergy Alternatives for Multi-Device and Multi-Monitor Control in 2025

Managing multiple devices and monitors efficiently matters more than it used to, now that most people juggle a work laptop, a personal machine, and a tablet on the same desk. Whether you’re a developer running tests on three operating systems at once, a designer bouncing between a Mac for creative work and a PC for client feedback, or just someone who hates reaching for a second keyboard, switching between screens without interruption saves real time over a workday. Synergy built its reputation solving exactly this problem, letting one keyboard and mouse control several computers at once. It isn’t the only option anymore, though, and a lot of users have started looking elsewhere over pricing, performance, or compatibility complaints.

Why Look for a Synergy Alternative?

Synergy is well known, but it comes with real drawbacks once you dig past the marketing page. The most common complaint is the pricing model, since advanced features sit behind a paid license rather than being included outright. On top of that, users report lag and inconsistent performance, especially when bouncing between different operating systems mid-session rather than staying on one platform all day.

Security is the bigger issue for a lot of teams. Synergy’s encryption is locked behind the paid tier, which means anyone running the free version is sending keystrokes and clipboard data across the network without protection. That’s a hard sell for anyone working with client data or company credentials. Compatibility gaps add to the frustration too, particularly for Mac and Linux users who often report a rougher experience than what Windows users get. Between the cost, the lag complaints, and the security gap on the free tier, it’s not surprising so many people go looking for something else. A freelance developer switching between a Windows testing rig and a MacBook for client calls, for example, is exactly the profile that runs into Synergy’s cross-platform quirks first, since that mixed setup exposes the inconsistency that a single-OS user would never notice.

What to Look for in a Multi-Device and Multi-Monitor Control Tool?

A few things separate a genuinely useful alternative from one that just looks good in a feature list. Seamless device switching comes first: the cursor needs to move between screens without a noticeable stutter, because that lag is the entire reason people abandon these tools. Cross-platform compatibility matters just as much if your setup spans Windows, macOS, and Linux rather than staying inside one ecosystem.

Security and encryption deserve real scrutiny, not just a checkbox on a features page, especially in any professional setting where sensitive data crosses the network between devices. And the extras, things like clipboard sharing, drag-and-drop file transfers, and customizable hotkeys, are what turn a basic KVM replacement into a tool you’d actually recommend to a coworker. None of these alternatives get everything right, so weigh which of these four matters most for your specific setup before committing.

10 Best Synergy Alternatives for Multi-Device and Multi-Monitor Control

1. Barrier – The Best Free and Open-Source Option

Barrier is a genuinely strong open-source alternative to Synergy, forked from an earlier open-source release of the original project. It delivers solid cross-platform compatibility, letting you control multiple devices from a single keyboard and mouse without paying a cent or creating an account.

What people tend to like most is how little there is to configure. There’s no bloated settings menu or upsell screen pushing a premium tier, just a straightforward setup that works. The tradeoff is that development has slowed in recent years compared to commercial competitors, so newer OS versions occasionally need a workaround before Barrier catches up.

2. ShareMouse – User-Friendly with Advanced Features

ShareMouse leans hard into ease of setup. Rather than making you manually configure IP addresses or connection settings, it automatically detects other devices running the software on the same network and lets you drag your cursor straight across screens.

It supports drag-and-drop file transfers, clipboard sharing, and even remote locking, which is a nice touch if you step away from a shared workstation and want to lock every connected screen at once. Professionals managing several machines in a home office tend to get the most value out of the automatic detection alone.

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3. Input Director – Ideal for Windows Users

If your whole setup lives inside the Windows ecosystem, Input Director is worth a serious look. It’s built for low-latency performance, so keyboard and mouse input stays responsive even when you’re bouncing between three or four machines in a testing lab.

Unlike Synergy, which gates encryption behind a paid subscription, Input Director includes strong encryption in its free tier. The catch is that it’s Windows-only, so it won’t help at all if a Mac or Linux box is part of your setup.

4. Mouse Without Borders – Free Microsoft Tool

Built by Microsoft Garage, Mouse Without Borders is a genuinely useful free tool for anyone running multiple Windows machines. It handles up to four computers with a single set of peripherals, which covers most home office and small studio setups without any extra hardware.

The drag-and-drop file transfer between machines is the feature people mention most, since it removes the need for a shared network drive just to move a file from one desk to another. Like Input Director, it’s Windows-exclusive, so it won’t solve a mixed-platform setup.

5. Multiplicity – Professional-Grade Software

Multiplicity targets businesses and professionals who need enterprise-level security more than they need a free price tag. Connections are encrypted end to end, and device switching stays smooth even under a heavier workload than most home users generate.

It’s paid software, and that shows in the polish: fewer bugs, more consistent performance across updates, and support that actually responds when something breaks. For an IT department managing dozens of workstations, that reliability is usually worth the license cost on its own.

6. Logitech Flow – Perfect for Logitech Users

If your desk is already stocked with Logitech peripherals, Flow is close to a zero-effort setup. It’s built directly into Logitech’s own software, so there’s no separate app to install or account to create.

It handles smooth cursor transitions and clipboard sharing between devices without much configuration. The obvious limitation is that it only works well with Logitech keyboards and mice, so it’s not a fit if your hardware comes from a mix of brands.

7. Across – Bluetooth-Based Multi-Device Control

Most alternatives on this list rely on a shared network connection, but Across takes a different approach and uses Bluetooth instead. That makes it a solid pick for anyone who moves between a laptop, a tablet, and other Bluetooth devices throughout the day rather than staying at one desk.

The wireless-first design is genuinely useful for people working on the go, in coworking spaces, or anywhere a Wi-Fi network isn’t reliable enough to trust for this kind of real-time control.

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8. KVM Switches – Hardware-Based Alternative

For anyone who’d rather avoid software altogether, a physical KVM (Keyboard, Video, Mouse) switch sidesteps the lag, connectivity drops, and licensing headaches that come with every software option on this list. A single button press swaps which machine your keyboard and monitor are talking to, instantly.

It does mean buying extra hardware, but the payoff is zero network latency and no software vulnerability to worry about, which is exactly why a lot of IT departments still prefer switches for security-sensitive workstations.

9. Remote Desktop Software – When You Need Full Access

Sometimes the actual need isn’t sharing a keyboard across two monitors, it’s getting full remote control of a machine that isn’t in the room. Tools like AnyDesk and TeamViewer solve that different problem, letting you operate a second device completely from wherever you are.

These aren’t a direct swap for Synergy in daily multi-monitor use, but for IT support tickets or working from a machine you don’t have physical access to, they cover a gap none of the other tools on this list can.

10. Universal Control (for Apple Users)

If every device on your desk runs macOS or iPadOS, Universal Control is hard to beat simply because it’s already built in. There’s no third-party app to install and no account to configure, just System Settings and a cursor that moves between your Mac and iPad on its own.

The obvious catch is that it only works within Apple’s own ecosystem. The moment a Windows or Linux machine enters the picture, Universal Control stops being an option and one of the cross-platform tools above becomes necessary instead.

Matching the Tool to Your Actual Setup

The right pick here depends less on which tool has the longest feature list and more on what your desk actually looks like. A mixed Windows and Mac setup rules out the platform-exclusive options like Mouse Without Borders or Universal Control immediately, no matter how well they work within their own ecosystem. If you’re already inside one ecosystem, though, the native or platform-specific tool is usually the smoother experience, since it was built with only that platform’s quirks in mind.

Budget plays a role too, but not always in the direction people expect. Barrier costs nothing and covers the basics well, so paying for Multiplicity only makes sense once you actually need the extra reliability and support that come with a commercial license, not just because a paid tool sounds more serious. Security-conscious teams handling client data should treat encryption as non-negotiable rather than a nice-to-have, which quietly rules out running Synergy’s free tier at all.

How These Options Compare on Price

Cost is often the deciding factor once two tools tie on features, so it’s worth laying out the general pattern before you commit. Barrier, Input Director, and Mouse Without Borders are all free with no catch, which makes them the obvious starting point if your setup fits within their platform limits. Logitech Flow is also free, but only functions as a bonus feature bundled with Logitech hardware you’d likely be buying anyway.

ShareMouse and Across both offer free tiers with limits on the number of connected devices, unlocking full functionality through a one-time purchase or subscription depending on the plan. Multiplicity sits at the top of the price range as dedicated commercial software, positioned for businesses that need guaranteed support rather than individuals optimizing a home office. KVM switches are a separate category entirely, with hardware costs ranging from budget two-port models to rack-mounted units built for server rooms, so the “price” comparison there is really about build quality and port count rather than a software license tier.

Setting Up Your First Multi-Device Connection

Getting a software-based option running for the first time usually takes less effort than people expect, though a few steps trip up first-time users consistently. Start by confirming every device sits on the same local network, since most of these tools, Barrier and ShareMouse included, look for other instances on the same subnet rather than searching the wider internet. A guest Wi-Fi network that isolates devices from each other will block discovery even if both computers are technically online.

Next, decide which machine acts as the “server,” meaning the one whose keyboard and mouse you’ll actually be using, since the others connect to it as clients rather than the other way around. Getting this backwards is the single most common setup mistake reported in user forums for nearly every tool on this list. Once the server and client relationship is set correctly, dragging the cursor across a screen edge should trigger the handoff, and if it doesn’t, the screen arrangement in the software’s settings almost always needs adjusting to match your physical monitor layout.

Common Setup Mistakes Worth Avoiding

A surprising number of multi-device control problems trace back to network configuration rather than the software itself. Running these tools over a crowded public Wi-Fi network, for instance, introduces exactly the kind of latency spikes that get blamed on the software when the real culprit is network congestion. A wired connection or a dedicated network segment fixes more lag complaints than switching tools ever does.

Skipping firmware and driver updates on peripherals is another quiet cause of dropped connections, particularly with wireless keyboards and mice that rely on their own receiver hardware. And running two multi-device control tools at once, which happens more often than you’d think when someone installs a new option without uninstalling the old one first, creates conflicts that neither piece of software handles gracefully.

Frequently Asked Questions

Is it safe to run a free multi-device control tool on a work computer?

It depends entirely on which tool and whether encryption is included in the free tier. Barrier and Input Director both include encryption without a paywall, which makes them reasonable choices even on machines handling sensitive work. Synergy’s free tier, by contrast, sends data unencrypted, which is exactly the gap that pushed a lot of users toward these alternatives in the first place. Check your company’s IT policy before installing any of these on a work device regardless of which one you pick.

Can these tools handle more than two monitors per computer?

Most of them handle however many monitors are already connected to each individual machine, since they’re controlling which computer receives input rather than managing monitor output directly. If one of your machines already runs a triple-monitor setup, moving the cursor onto that machine hands off control across all three screens at once, not just one.

Do any of these work over the internet, not just a local network?

Most of the software options here, including Barrier, ShareMouse, and Input Director, are built for devices on the same local network and aren’t designed for remote control across the internet. If you need to control a machine that’s physically somewhere else, that’s the use case remote desktop software like AnyDesk or TeamViewer solves, not a Synergy-style multi-device tool.

What happens if a device disconnects mid-session?

Behavior varies by tool, but most of the software options reconnect automatically once the device comes back on the network, without needing to relaunch the app or reconfigure anything. KVM switches don’t have this problem at all since there’s no network dependency, which is part of why some IT teams still prefer the hardware route for anything mission-critical.

Find Your Perfect Synergy Alternative Today

With this many Synergy alternatives for multi-device and multi-monitor control, there’s no reason to stick with software that doesn’t fit how you actually work. Whether you want a free and open-source option like Barrier, a high-security professional tool like Multiplicity, or an Apple-exclusive feature like Universal Control, there’s something built for your specific setup rather than a generic one-size-fits-all pitch.

Each alternative brings its own tradeoffs between cost, security, and platform support, and none of them wins on every axis at once. Take a few minutes to check what your actual hardware mix looks like, test one or two of the closest matches from this list, and let the results decide rather than the marketing copy on each product’s homepage.

If you’re still unsure where to start, the platform question settles most of it on its own. All-Windows setups do best with Input Director or Mouse Without Borders, all-Apple setups already have Universal Control built in for free, and anyone mixing operating systems should start with Barrier before paying for anything. Everything else on this list is a refinement once that first, cheaper option turns out to be missing a specific feature you actually need day to day.

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