How to Fix Slow XML Parsing in React Native

Mike Ouroumis — Sat, 29 Nov 2025 03:49:36 +0000

If you've ever parsed XML in a React Native app, you've probably noticed the pain: your UI freezes, animations stutter, and users wait. The culprit? JavaScript XML parsers run on the JS thread, blocking everything else.
I hit this problem on a project where XML parsing took over 8 seconds on low-end Android devices. After moving to a native solution, it dropped to under 2 seconds. Here's how to fix it.

Why JavaScript XML Parsing Is Slow

Popular libraries like react-native-xml2js work fine for small files. But they have a fundamental problem: they run on the single JavaScript thread.
While parsing happens, your app can't respond to touch events, update animations, or render UI changes. On older devices or with large XML files, this means frozen screens and angry users.

The Solution: Native XML Parsing

Native code (Kotlin on Android, Swift on iOS) can parse XML on a background thread. The JS thread stays free, your UI stays responsive.

Use react-native-turboxml

I built react-native-turboxml to solve this exact problem. It's a TurboModule that parses XML natively using Kotlin coroutines on Android.

npm install react-native-turboxml

import { parseXml } from 'react-native-turboxml';

const result = await parseXml(xmlString);

That's it. Parsing happens on a background thread, returns a JavaScript object, and your UI never blocks.

When to Use Native XML Parsing

Use native parsing when:

XML files are larger than 50-100KB
You're targeting low-end devices
Parsing happens during user interaction

For small config files parsed once at startup, JavaScript parsers are fine.

Bonus: Parallelize with Promise.all

const [data1, data2, data3] = await Promise.all([
    parseXml(xml1),
    parseXml(xml2),
    parseXml(xml3),
]);

Conclusion

JavaScript XML parsers block your thread and hurt performance. Moving parsing to native code keeps your UI responsive.
The easiest fix: install react-native-turboxml and replace your parser calls.