Building a Contest Alarm App for Codeforces & AtCoder — Need Suggestions

#help #kotlin #android #mobile

Short Intro:

As a competitive programmer, missing a contest because of unexpected schedule changes is frustrating. I’m building a mobile app that automatically tracks contests on platforms like Codeforces, AtCoder, and CodeChef, detects time changes, and sets a loud, unmissable alarm before the contest starts(need alarm 30 minute before contest start). I’m looking for suggestions, guidance, and advice from developers who’ve built similar apps or worked with mobile alarms and background tasks.
Hi everyone!
I want to build a mobile app for competitive programmers that ensures I never miss a contest, even if the scheduled time changes unexpectedly.

Project Idea

The app will:

Automatically fetch upcoming contests from Codeforces, AtCoder, CodeChef, and others.
Detect schedule changes and reschedule alarms automatically.
Trigger a loud, full-screen alarm (not just a notification) before the contest.
Allow users to customize the alarm time (e.g., 15, 20, 30, or 45 minutes before).
Be extensible to additional contest platforms in the future.

Key Features

Automatic Contest Fetching

Uses APIs (or scraping if necessary) to get up-to-date schedules.

Time-Change Detection

- Compares API data with local storage
Cancels previous alarms if the contest time changes
Sets new alarms based on updated start time

Customizable Alarm Offsets

Default: 30 minutes before
Optional: 15, 20, 45 minutes or any custom interval

Loud, Reliable Alarm

Full-screen activity
Rings even if the phone is locked or in silent mode
Custom sound

Multi-Platform Support

Designed to support Codeforces, AtCoder, CodeChef, and future platforms

Help Needed

I’m looking for guidance on:

Best development approach: Native Android (Kotlin) vs Flutter vs React Native
Background syncing: WorkManager, AlarmManager, foreground services, or hybrid approach
Reliable alarm scheduling: How to survive app kills, Doze mode, and battery optimization
Data management: Best practices for local storage, detecting updates, and rescheduling alarms.

Give me overall guidance what should I learn and need.

I’d love advice from developers who have worked on: