QuizMonster
Kids quiz app · from November 2026 · Founder, Full-stack
A quiz with a monster who cheers you on.
QuizMonster is a quiz app for children aged 6 to 12. A friendly monster reads the question, waits while you think, and celebrates every right answer. There is no red and no X: a wrong answer gets an encouraging thumbs up and another go. Bombo, Nina and Chip each have their own personality, and every quiz turns into a small show.
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What Krnic did
Designed and built from scratch as an Expo and React Native app on a hand-built cartoon design system: cream surfaces, four pastel answer colours, chunky rounded type in Baloo 2 and Nunito, big touch targets, warm haptic feedback, and reduced motion respected throughout.
The monsters are not rigs. They are AI-rendered video clips with transparency, produced by a pipeline of Nano Banana Pro for the master pose, Kling v3 Pro for image-to-video with the same first and last frame, Bria for matting and ffmpeg for encoding: HEVC with alpha for iOS, VP9 with alpha for Android and web, animated WebP as fallback. Because every clip starts and ends in the neutral pose, a small character state machine cuts from idle to a reaction and back without a visible seam.
Stack: React Native, Expo, TypeScript, Reanimated, expo-video, Kling, Nano Banana, Bria, ffmpeg, Python