HomeBlogLocking and unlocking should not cost the same
Locking and unlocking should not cost the same
A blocker that costs as much to switch off as to switch on gives the final say to your most tired self. Why Spark makes locking free and unlocking a walk.
DesignPublished Updated 6 min read
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Open any focus app and you will find a switch. Flip it on, the apps go away. Flip it off, they come back. The two directions cost exactly the same: one tap each. That evenness looks like good design, and it is the reason almost none of them work.
You are not the same person all day
The one who sets up a blocker does it on a good day, with a plan and next week in mind. The one who switches it off does it at the end of a bad one — tired, bored, and thinking no further ahead than the next few minutes. The two share a phone and a name, and almost nothing else. A switch that costs the same both ways gives the tired one all of the planner's authority, and hands it over at the worst possible time.
A lock you can open lying down will be opened lying down.The full argument
The same argument at full length: what people try first, the way each of those fails, and what a physical key still cannot do.
Read thisMake the two directions different
Spark deliberately breaks the symmetry. Once your Spark is paired, locking is instant and costs you nothing: one tap, or a schedule — no key, no Bluetooth, no network, no waiting. We never want friction between you and the decision to focus. If locking were annoying you would simply stop doing it.
Unlocking is the one direction with a gate. You have to hold your phone against the key — for about 15 seconds with the Bluetooth Spark, a tap with the NFC one — before it will give the apps back. Leave the key in a drawer in another room and the cost of caving is no longer a tap — it is standing up. That is the whole trick: a willpower problem becomes a walking problem, and an urge has to last the whole walk to win.
- Lock: instant, keyless once paired, works with Bluetooth off and no signal.
- Unlock: hold your phone against the key for about 15 seconds, or tap the NFC Spark.
- Both directions are honest about what they can and cannot enforce.
Why the key moved from NFC to Bluetooth: the phones with no NFC reader, and what the move gave up. An NFC Spark is sold alongside it again today.
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One tap in the app, or a schedule. Instant, offline, and the key does not need to be in the room. Nothing should ever stand between you and locking.
Hold your phone against the key — about 15 seconds for the Bluetooth Spark, a tap for the NFC one. Leave it in another room and the cheapest route back to the feed is standing up.
Why not just a timer?
Timers fail in the other direction: they are impossible to undo even when you genuinely need to. A parent needs their phone in an emergency. A timer that cannot be broken is a liability, and one that can be broken with a tap is decoration. A physical key sits in between — a real cost, never free, and one you can pay whenever you are willing to walk.
That is the entire product thesis. Everything else is implementation.
The implementationWhat the tap actually does, what unlocking takes before the apps come back, and why locking still works with Bluetooth switched off.
Read thisThe rest of the argument
Each post stands alone. If you would rather have instructions than opinions, the guides are the maintained layer.
Why a focus tool shouldn't be a subscription
A subscription pays its maker for as long as you still need it. Why Spark is a free app and a key bought once, and what that key can and cannot enforce.
5 min readEngineering · 29 Apr 2026Why we replaced the NFC tag with a Bluetooth key
Why the first Spark moved from an NFC tag to a Bluetooth key, what we thought we were giving up — and what has changed since.
6 min readPut the unlock in another room.
Once your Spark is paired, locking is one tap and works with Bluetooth off. Unlocking means walking to the key and holding your phone against it — which is the whole difference between deciding to stop and having to stand up. The app is free; the key is the one-time buy.