Focus timer · Desktop, Android, iOS
Your device stays locked until the code is correct and fast.
Set a timer. Work. When it fires, the screen belongs to CodeLock until you solve the problem it assigns — and a solution that passes every test but runs in quadratic time does not open the machine.
Two Sum · JavaScript
gate = best 108ms × 1.35 + 40ms = 186ms
still locked · roughly 3.8× slower than the best known answer
The same arithmetic the judge applies. Run your own code against it →
01 / The lock
The server decides, not the app.
Clients never conclude they are unlocked. The API signs a token bound to one user and one session, issued only after the judge passes and the speed gate clears. The desktop shell verifies that signature in a process the web view cannot reach.
Patch the front end, open the console, call the unlock channel by hand — the signature fails and the overlay stays.
02 / The gate
Correct is not the bar.
Your fastest of two runs has to come in under best × 1.35 + 40ms, measured inside the sandbox rather than around it, with a separate budget per language.
Miss it and you get the number, not a shrug: 2.1× slower than the best known solution. The lock stays on. Write the better algorithm.
03 / The ladder
Difficulty you can predict.
Two fast solves out of three moves you up. Two failures move you down. That is the whole rule, and it is the rule the interface shows you.
No hidden score, no opaque model deciding your morning. You can always tell what would happen next.
Limits
It is a commitment device, not a parental control.
Every platform has a deliberate way out, and pretending otherwise would be the fastest way to lose your trust the first time you found one.
The design goal is that none of them happens by reflex, and that the cheap escapes cost you a recorded failure.
- Desktop
- Kiosk overlay on every display, survives a kill, a crash and a reboot. Ctrl+Alt+Del or a power-off defeats it.
- Android
- A real overlay above other apps, restored after a reboot. Force-stop, Safe Mode or uninstall defeat it.
- iOS
- Takes over its own screen and notifies you. No app can block another. Not a limitation of ours.
- Browser
- Not a lock surface at all. A tab can always be closed.
Install it, arm it, then go and work.
CodeLock only makes sense installed. A tab you can close is not a lock, and we are not going to pretend otherwise.