You already know React. Now ship mobile.React Native + Expo in TypeScript. Real tests. No videos.
Two courses that take a React developer from their first View to an app shipped through EAS Build. Every exercise is graded by hidden tests against your actual rendered components — so “it works” is never a vibe. No Swift, no Kotlin — the React you know, on phones.
// LikeButton: toggle the liked state on press.
// Hidden tests render this component and assert on the actual output.
export function LikeButton({ initial }: { initial: number }) {
const [liked, setLiked] = useState(false);
const [count, setCount] = useState(initial);
return (
<View style={styles.row}>
<Pressable
onPress={() => {
setLiked(!liked);
setCount(count + (liked ? -1 : 1));
}}
>
<Text>{liked ? "♥ Liked" : "♡ Like"}</Text>
</Pressable>
<Text testID="count">{count}</Text>
</View>
);
}React Native Foundations
View, Text, Pressable and FlatList, styling with Flexbox, Expo Router navigation, and app state and data fetching — through capstones like a Recipe Browser, a Movie Watchlist, and a Checkout Flow.
Device, Offline, Performance & Ship
Device APIs and permissions, offline-first sync, render performance, RNTL testing, and the EAS Build / OTA publishing pipeline nobody teaches interactively — ending in Ship a Real App.
The tests decide, not vibes
Hidden tests render your component and assert on what it actually outputs — the label, the count, what a press changes. Pass/fail is deterministic — the AI never grades you.
It adapts to you
Struggle on a concept and the game diagnoses why and builds targeted practice. Already comfortable with FlatList? It moves you up instead of making you sit through it.
Ship real apps
Capstones like an Offline Movie Watchlist, a Performance Rescue, and a real EAS Build submission — the answer to tutorial hell. Ship a portfolio, not just streaks.
Your first passing component test is minutes away.
Start the mobile track — freeFree tier is genuinely free — every banked exercise is playable. We gate AI help and fresh generation, never the content.