One keyboard.Every Mac.

No. Continuo is commercial proprietary software. A buildable security package containing the pairing, identity-pinning, and secure connection-admission code consumed by the product is published and available for audit. It also contains a staged and tested generic SessionCrypto implementation, which is not the shipped input-encryption implementation. The motion engine, trackpad code, and Pro features remain proprietary.

Deskflow is a good project: free, actively developed, and the right choice if Windows or Linux shares your desk, which Continuo does not cover. Continuo is built only for the Mac. It is signed and notarized, so it installs without a Terminal step (Deskflow's README says it does not notarize, and macOS reports it as damaged until the quarantine flag is cleared). And it does things Deskflow does not: drag a file straight into a window on another Mac (free), plus folders and batches, Quick Share to mount a folder from another Mac in Finder, Copy on Select, waking a sleeping Mac, and Mesh Sleep Sync (Pro). The full list is on the compare page.

Not yet, byte for byte. The security source is published and available for audit. Release-to-source mapping is planned; when it ships, each signed release will record the security-source commit in the whitepaper. The generic SessionCrypto implementation remains staged and is not the shipped input-encryption implementation.

No. Your Macs have to be on the same Wi-Fi or plugged into the same network. Keyboard, mouse, clipboard, and file content travel only on the authenticated peer connection between paired Macs. None of it is sent to an Internet service.

No. This is not screen sharing. Each Mac keeps showing its own screen. What moves between them is your keyboard, mouse, clipboard and files.

No. Different Apple IDs are fine, and so is no Apple ID at all. They recognise each other directly, without going through Apple.

Yes, in both directions. Each Mac verifies it is talking to the paired machine, not an impostor. There is no switch to turn encryption off.

No telemetry and no analytics in the app. There is no account and no cloud relay for your input. Diagnostic logs stay on your Mac with keystroke content stripped out. Update checks only add to a daily count per app version. The Pro trial sends a one-way device hash. Licence activation sends that hash plus a device name, so seats are listed by something you recognise; see the privacy policy. Purchases go through Polar.

Free: two Macs, encrypted keyboard and mouse, Pair with three words, layout, QuickJump, locking the pointer to one Mac, Auto-reconnect, menu bar status, clipboard text and images up to 1 MB, and one file at a time. Pro: 5 Macs included on one licence, trackpad gestures, Copy on Select, Wake-on-LAN and Wake them automatically, Mesh Sleep Sync, putting every Mac to sleep when you sleep one, locking every Mac when you lock one, folders and batch files, Quick Share folder mounting (both Macs need Pro), clipboard up to 32 MB, keyboard on a locked Mac, logging in at the login window after a log out or a restart. Trackpad gestures, the locked Mac, locking every Mac at once and putting every Mac to sleep need Pro on both Macs. Pairing a third Mac is itself a Pro feature; licence activations are capped separately, per Mac.

Only if you want new builds. Your purchase includes one year of new builds, which normally covers the next macOS release. After that year, the app keeps running with every Pro feature, permanently. Optional update feed access is $19/year if you want it. That is not a subscription, and your Pro licence does not expire.

Any Mac on macOS 15 or newer, as long as they are on the same network.

No, and not one I am planning. Continuo is one macOS app: it uses macOS event taps for input, macOS permission prompts, and an NFS mount for Quick Share, so a Windows version would be a new product rather than a port. If there is a PC on your desk, Deskflow is free and covers Windows and Linux, and Synergy sells a paid version that does too. Continuo is for the desk where every machine is a Mac.