CakeTax

It keeps a Bluetooth Low Energy connection to the device you paired and reads the signal strength every couple of seconds. Signal falls off with distance, so when it stays past your chosen threshold — or the device leaves range — for your chosen delay, the Mac locks.

iPhone and Apple Watch work best — their iCloud identity gives the strongest pairing, and the hardest to spoof. Android phones, smartwatches, tags and other Bluetooth LE devices work too, provided they broadcast a stable identity; the setup walk test verifies that before anything is trusted.

Yes — phone and watch, say. Pair the second one in Settings → Distance with the same one-minute walk test, and the settings show each device's own live signal and distance, each drawn as its own line on the signal graph.

You pick the rule, in Settings → Distance:

Both devices are gone (the default): the Mac counts as attended while either device is near, so whichever one you happen to carry keeps it unlocked. The nearest device's signal decides.

Either device is gone (strict): the Mac locks as soon as any device moves past your distance — here the farthest device's signal decides. Note what strict means: a device that isn't with you at all counts as gone, so leaving one at home locks the Mac after the out-of-range patience.

Only one device decides: pick which. The other stays visible in the settings and on the graph, but it neither keeps the Mac unlocked nor locks it — handy when the phone lives on the desk all day and only the watch should matter.

Whatever the rule, the settings show a "Deciding signal" row naming the device currently driving the decision, so what you see is what the app is acting on.

For Apple devices, your Mac and the iPhone/Watch must be signed in to the same Apple ID — that's what lets the Mac recognise them through Bluetooth's privacy address rotation. Also wake the device and keep it next to the Mac while scanning. If it still hides, toggle Bluetooth off and on, on both devices.

macOS 14 (Sonoma) and later.

No. Your phone already broadcasts Bluetooth LE for AirDrop and Handoff; CakeTax listens and connects from the Mac side. There is no app running on the phone.

CakeTax lives in the menu bar and works in the background. Turn on "Launch at login" in Settings → Advanced and you never think about it again.

Yes — in metres, not radio jargon. Use the slider, pick a preset (arm's reach, at my desk, same room, left the room), or press "Set From Where My Device Is Now" with the device placed exactly where locking should begin.

Several guards catch this. CakeTax never locks while you're typing or moving the mouse; brief dips are smoothed away and forgiven by your lock delay; the app knows when macOS throttled its own readings and never mistakes that silence for you leaving; and every lock is explained afterwards in Settings → Activity → "Why did it lock?".

No. CakeTax locks once per departure, by construction: after a lock it disarms, and it only re-arms when your device actually comes back within your distance (plus a safety margin). So if you unlock with your password while the device is still elsewhere, the Mac stays unlocked — for minutes or hours — until a device returns and leaves again. There is no loop to fall into. On top of that, a configurable cooldown holds fire right after any unlock, it never locks mid-typing, and for planned "my phone is elsewhere today" days there's Pause in the menu bar and safe zones. This exact scenario is covered by an automated test in the engine.

After you unlock, CakeTax waits a configurable cooldown (up to 180 s) before it can auto-lock again, so an unlock at the edge of range can't flap. Settings → Advanced also exposes the re-arm margin (hysteresis) and out-of-range patience if your environment needs tuning.

Bluetooth signal strength is honest physics: dependable at "left the desk" and "left the room", not a tape measure. Walls, bodies and pockets shift it. Tune by feel — the metre figures are a dial, not a measurement.

Modern phones randomise their Bluetooth address precisely to stop that kind of tracking. CakeTax pairs with one chosen device whose identity it can verify — which is also what makes the pairing trustworthy.

On notched MacBooks, macOS silently hides menu bar icons that don't fit. CakeTax detects this and warns you; free space by removing icons you don't need (⌘-drag them off the bar). Auto-locking keeps working even while the icon is hidden.

No, and that's deliberate. Auto-unlock generally requires storing your macOS password and typing it into the login screen for you. We think a security tool shouldn't hold the key to your Mac — and with Touch ID and Apple Watch, unlocking is already instant. CakeTax locks. That's the job.

Your choice, in Settings → Rules: by default CakeTax pauses (a radio outage isn't you leaving), or flip one switch and the Mac locks the instant Bluetooth goes down — because that's also the first thing a tamperer would try.

Release builds will be signed with an Apple Developer ID and notarised by Apple. That check confirms the app hasn't been tampered with and screens it for malicious code. Closed-beta builds are handed out before that is in place, so macOS will warn you the first time you open one and testers are told to expect it. Once CakeTax is on sale, a Gatekeeper warning on a CakeTax build means the build isn't ours. Don't bypass it.

No. It runs fully offline. The only network features are the update check and opt-in anonymous statistics — both described in the privacy policy, and the statistics are off until you switch them on.

Locking the screen instantly uses a system call the App Store doesn't permit, so CakeTax is sold here instead — signed and notarised through Apple's Developer ID process, like most serious Mac utilities.

Fill in the form above. We read every entry and send invited testers a personal download link by email — we're keeping the group small enough that everyone gets a real reply and every report gets read. Tell us what device you'd carry and where you'd use it; that's how we pick for spread rather than first-come-first-served.

Free for beta testers. At launch it is €19 once, or $19 in the US, with VAT included for buyers in the EU. There is no subscription. You get a 14-day trial without a card and a 30-day money-back guarantee, and beta testers get a discount code.

Every 1.x update is free. When version 2.0 arrives it will be a paid upgrade, and you'll get a discount for already owning CakeTax. A major version takes months of work, and this is how that gets paid for.

Yes — one purchase covers all Macs you personally own and use.

Email hello@caketax.app (or beta@caketax.app for beta feedback). Include the "Why did it lock?" entry from Settings → Activity if it's about a lock you didn't expect — that's usually all we need.