ScreenFine

Why ScreenFine exists

Every digital-wellbeing app on the App Store leaves you free to ignore it. ScreenFine asks what happens when you cannot. The answer is loss aversion. And the smallest possible mechanism that creates a real, dated loss.

The story starts the way these stories always start. A founder who installed Apple Screen Time, smashed through the daily limit, tapped Ignore for today, and noticed. With a kind of quiet horror. That the sequence had become a ritual. Limit. Override. Repeat. The "consequence" of going over was a beige banner. The "cost" was nothing.

So we tried Opal. We tried One Sec. We tried ScreenZen, Brick, Roots, Forest, Jomo. Each of them solved a slice of the problem. The compulsive open, the deep-work block, the gentle nudge. Each of them, eventually, got bypassed. Either the friction adapted away or the willpower ran out, usually before the end of the second week.

The thing missing from every one of them was the same thing: a real consequence. The kind of consequence that changes behaviour not because you decide it should, but because the deal is already signed. A pre-commitment. A Ulysses contract. A bet you make against yourself when the rational version of you is in charge, redeemable when the 11:47pm version is.

That is what ScreenFine is. The whole product is a pre-commitment device for screen time. You set the limit. You agree, in advance, that going over locks the offending apps until you do 25 pushups, walk 1,000 steps, or sit through 10 mindful minutes. You choose the redemption type at onboarding. When the limit is crossed, the apps lock. There is no override button. There is no ignore for today. There is a notification from an AI villain who is unsparing about it.

And then there is a 1-week redemption window where you can clear the lock by walking 1,000 steps, doing a workout, 10 mindful minutes, or 25 camera-counted pushups. Because the goal is behaviour change, not punishment. Most lock events never make it past the redemption window. The ones that do, hold the apps locked until you complete the action. That is the trade.

The four ideas behind the product

Loss aversion is real

Daniel Kahneman and Amos Tversky showed in 1979 that humans treat losses as roughly twice as motivating as equivalent gains. Every screen-time app on the App Store is built around gain framing. "save time", "find balance", "be more focused". ScreenFine is built around loss framing. Losing access to your apps until you do 25 pushups is a real, immediate loss in a way a notification is not.

Friction is not enough

A pause before Instagram works for some people for some weeks. Then the muscle memory adapts and the pause becomes part of the loop. The same is true of scheduled blocks, dim-screens, app limits, and breathing prompts. A consequence that costs you something is the smallest mechanism that does not adapt away.

Pre-commitment is the play

Ulysses tied himself to the mast before the sirens. ScreenFine asks you to set the limit when you are calm and then puts a verified-exercise penalty on the next 11:47pm. By the time the urge hits, the deal is already done. You are not negotiating with yourself in the moment. The contract was signed in advance.

Redemption beats punishment

Each lock is pending for 1 week. You can clear it by walking 1,000 steps, doing a workout, ten mindful minutes, or 25 camera-counted pushups. The lock is a prompt, not a verdict. The goal is sustained behaviour change, not punishment.

Built by Stacklance

ScreenFine is a product from Stacklance, a small iOS product studio focused on apps where the mechanism matters more than the marketing.

The technical stack: native iOS Screen Time integration via the FamilyControls + DeviceActivityMonitor + ManagedSettings APIs (the same APIs Apple uses for parental controls), on-device camera-based exercise verification via the iPhone TrueDepth sensor, HealthKit for step verification, a Convex backend for lock-state tracking and the AI villain pipeline, OpenRouter (default model: Claude Haiku 4.5) for the villain copy generation, and Apple IAP as the merchant of record for the $1/week subscription. No other charges.

The behavioural-economics framing is grounded in published research. The Kahneman/Tversky prospect-theory paper (1979) established loss aversion empirically. The Ayres/Karlan StickK work at Yale showed that verified-exercise commitment contracts produce sustained behaviour change in habits ranging from smoking cessation to gym attendance. ScreenFine applies that mechanism, automated and screen-time-specific, to phone use.

What ScreenFine is not: it is not parental control software, it is not a coaching app, it is not for everyone. It is for adults who have already tried friction-based screen-time tools and bypassed them within a month. If that is you, the mechanism is built for you. If it is not, Apple Screen Time is genuinely good and free.

Studio: stacklance.in · Press: press kit · Contact: help​@​screenfine​.​info

See if it works on you

$1 a week. Real consequences. Pause anytime. 7-day trial. If loss aversion does not move you the way it moved us, cancel before day 7 and pay nothing.