Inspiration

I'm a 15-year-old high school student in Turkey. Every time I sat down to study, I ended up on my phone five minutes later — and all my friends had the same problem. Existing apps were easy to cheat, so I wanted to build one that actually makes you keep your promise to yourself. That's where the name comes from: an oath you can't break, because it's locked.

What it does

Oathlock is an Android focus app:

Real app blocking – pick distracting apps from the list of apps installed on your phone; during a focus session, opening them shows a block screen.
Math alarm – built on Android's native alarm system; to turn it off you have to solve math problems, so you're actually awake.
Tasks with deadlines and reminders – notifications arrive on time, even after a restart.
AI coach – powered by Gemini; tell it "I can't start studying" and it gives you a short, practical plan.
Screen time stats – see how much time you spend on your phone.
3 languages – English, Turkish and German.
Oathlock Pro – $4.99/month or $40/year, powered by RevenueCat.

How I built it

React 19 + TypeScript + Vite + Tailwind, wrapped with Capacitor 8 for Android.
A custom native Java plugin for the parts the web can't do: Accessibility Service (app blocking), AlarmManager (alarms), UsageStats (screen time), foreground services and boot receivers.
RevenueCat SDK for subscriptions: one "pro" entitlement with monthly and yearly products, shown through an offering in the paywall.
Google Sign-In for accounts and the Gemini API for the AI coach.
I used AI coding assistants to learn and move faster, while I designed the app, tested every feature on my own phone and made the decisions.

Challenges I ran into

Making app blocking reliable on Android with the Accessibility Service.
Making the alarm ring like a real alarm even when the phone is locked or the app is closed.
Setting up RevenueCat products, entitlements and offerings correctly for the first time.
Translating both the app interface and the native Android notifications into 3 languages.