Why a focus tool shouldn't be a subscription

Every software-only blocker eventually meets the same adversary: a determined user with administrator rights over their own device. That user knows the uninstall path, the settings toggle, the safe-mode trick. They are not a hacker. They are you, at 11pm.

Friction that cannot be optimised away

Software friction erodes. A confirmation dialog gets read properly once, skimmed the next few times, and before long dismissed on reflex without a word of it registering. A countdown goes the same way: sit through it a few times and you learn that sitting through it is all it asks.

Physical distance does not erode. The key is either in your hand, held against the phone, or it is somewhere else. You can learn to get through a dialog without reading it; there is no way to get through a walk to the next room without walking it, and — past five emergency unlocks, for life — nothing you can do on the screen stands in for it.

The key is only a key

Worth being precise about what the hardware does and does not do. The key does not block anything. It has no idea which apps you have chosen, it stores no usage data, and it never talks to the internet. All blocking is done by your phone, using the operating system's own official APIs — the Screen Time stack on iOS, an accessibility service on Android.

Those two stacks are not equally strong. Android allows a blocker to hold on more tightly than iOS does, and rather than quietly averaging the two into a promise we cannot keep on both, we document the difference and let you decide what it means for your phone. A key does not close the routes in the first paragraph, either: on iPhone you can still revoke the Screen Time permission or delete the app, which ends a session. What it removes is the easy route — the tap you would otherwise make without thinking.

The key's entire job is to answer one question: is it actually here, against the phone? It answers well enough for a tired person and not for a determined one. The Bluetooth key broadcasts a fixed identity, and someone who sets out to can record that broadcast and replay it; the NFC key is a standard tag that can be copied. What enforces the walk is the hold — about 15 seconds with the phone against the Bluetooth key, a tap on the NFC one — not a secret.

• The key knows nothing about your apps and never talks to the internet.
• Pairing it needs a sign-in and an internet connection.
• Your modes, schedules, limits and sessions then sync to Spark's servers, so a new phone can restore them.

One purchase, not a subscription

There is a second asymmetry here, and it is commercial. Software-only blockers are nearly all subscriptions, which puts the company on the wrong side of the incentive. A blocker you cancel is a blocker that stopped being worth paying for, so the product quietly gets optimised for renewal rather than for the day you no longer need it.

Spark is built the other way round. The app is free and stays free — no subscription, nothing behind a paywall. It does need a key to do anything: nothing locks until a Spark is paired. The key is the thing you buy, once, priced in rupees and quoted before GST, with free shipping to most of India. There is no recurring charge, nothing to cancel, and no version of this product that gets worse when you stop paying, because you already stopped.