The Hitchhiker’s Guide to React Native

Concurrent Renderer gives React Native the power to pause, prioritize, and resume rendering work—so your app stays responsive even under pressure. Instead of blocking the UI for every update, React now handles what matters first. It’s like switching from a to-do list to triage.

Fabric is React Native’s new rendering engine that aligns closely with React’s internals. It brings synchronous layout, better performance, and tighter control over UI updates—making rendering faster, more predictable, and actually React-like. Think of it as tearing out the rickety scaffolding and rebuilding the UI pipeline with steel beams.

JSI (JavaScript Interface) is a low-level C++ layer in React Native’s New Architecture that enables synchronous, direct communication between JavaScript and native code—no JSON, no async bridge, no waiting. It unlocks runtime flexibility, faster performance, and native-level access for libraries like Reanimated, Skia, and Nitro. Think of it as the power cable React Native always needed but never had.

The Battle of the Lists is the React Native community’s informal name for the performance race between FlashList (Shopify, 2022) and Legend List (Jay Meistrich / LegendApp, 2024–25). Both emerged to replace React Native’s built-in FlatList, long criticised for frame drops, blank cells during rapid scrolls, and poor handling of dynamic item sizes.

TurboModules are the next-gen way to call native code in React Native—sync, fast, and fully typed. They replace the old async bridge with JSI, letting JavaScript talk to native modules directly, with zero delays and less boilerplate thanks to auto-generated bindings from TypeScript. No bridge, no baggage.

A Universal App is a React Native application that targets mobile (iOS and Android) and the web from the same codebase. The term is meant to separate this idea from the older “cross-platform” label, which historically just meant “it works on both iOS and Android.” Universal shifts the scope: one repo, three major platforms.