Problem
Uzbekistan’s social life runs on Telegram and foreign apps. Zynygram set out to build a local social network that feels as smooth as Instagram, adds private chat and calls, and lets people generate images and videos with AI inside the same app.
What I built
I own the Flutter app end to end. Over five months it went from version 1.0 to 2.0.8, with the 2.0 “biggest update” redesigning chat, groups and calls and adding the AI studio. On the backend I wrote most of the AI gateway, the support chat and the recommendation service.
Front · Flutter
- Strict clean architecture: UI → BLoC → UseCase → Repository → DataSource, 16 feature modules that never import each other.
- About 148k hand-written lines, with a release gate every version has to pass.
- 1:1 voice and video calls with WebRTC and CallKit, including the Android lock-screen full-screen intent.
- On-device video compression with background upload, a share extension on iOS and Android, deep links and multi-account.
Behind · Servers
- Django, Channels and Celery with five queues, PostgreSQL 16, Redis and a Cloudflare CDN.
- A stress test reached 272 requests per second on 2 vCPU with 0% errors.
- Wire-contract rules (additive-only changes, an enum snapshot test, shims for old builds) keep slow-updating phones working.
Inside · AI
- An AI gateway with 16 image and video models from 4 providers, plus video bought through Klipmatic’s partner API.
- A fail-closed moderation ensemble: if checks fail, content stays hidden.
Hard problems
- Reels “player stampede”. Scrolling fast built many HLS players at once and stuttered. I capped concurrent builds at 2, newest first, then profiled real iPhones with VM timeline and Perfetto to confirm.
- Shipping betas without the stores. I built a per-account early-access track on Shorebird code push: users opt in from Settings and get beta patches inside the app.
- App Store rejection. The first submission was rejected; I traced a three-layer OAuth bug and added user blocking, and the next review passed.
Results
8K+ registered users, 5K+ monthly active users, ★4.9 on the App Store, and a release cadence of several versions a month.