Disclosure: I used AI to refine my blog as English is not my first language.

Used a couple of the CF Android apps over the past year (Ally being the main one) and they all have the same problems, so figured I'd just build my own instead of complaining about it.

Went back and read through the comments on Codeforces Ally's post before starting and a few stood out:

Who needs features when you have non-stop ads?

Can Somebody share the APK file

can we submit the code on the website from my PC. since typing on the phone will be difficut

plus a bunch about the groups tab being broken and contest tab showing wrong data. Basically the app works until it doesn't, and there's no way to trust or fix it yourself when it breaks.

So the plan: fully open source, code goes on GitHub, no ads anywhere, and auth happens entirely on-device (nothing gets sent to or stored on any server I run). You'll be able to get it from the Play Store if you just want it to work, or grab the APK from GitHub releases/F-Droid, or clone and build it yourself if you don't trust a random prebuilt binary.

Feature-wise, thinking contest calendar with alarms + calendar export (Google/Outlook/ics), a code editor that actually compiles and runs testcases before you submit instead of just being a text box, rating predictor, virtual contest mode, friend rating tracking, problem search by tag/difficulty. None of this is locked in yet.

Things I actually want opinions on: what do you check first after a contest ends, rank/rating change/editorial/upsolving, something that could just be automated for you? And for the code editor, do people want something closer to a real IDE with autocomplete and multi-file support, or just fast to open and type in? Also curious if anyone's used the existing CF apps long enough to say what specifically made them stop.

And would you actually bother building the APK yourself, or is that a feature that sounds nice but nobody uses in practice.