React-Native Downloader: Native HTTP Client for Multi-Gigabyte AI Model Files

I built a native React Native downloader because AI models are huge

Falaq built react-native-client to solve a practical mobile problem: downloading multi-gigabyte AI models for the offline app Orb. The package streams files directly to disk on the native side, bypassing the JavaScript bridge entirely.

Why This Matters

Local AI models offer strong privacy guarantees, but they create a brutal mobile UX bottleneck: model files are multiple gigabytes and typical app-level download logic fails under real-world conditions like bad Wi-Fi, app backgrounding, or force-closes. Restarting a failed multi-gigabyte download from zero is unacceptable; react-native-client solves this by streaming directly to disk and supporting resumable downloads via HTTP Range requests.

Key Insights

• Android uses OkHttp and iOS uses URLSession for native networking (react-native-client, 2026).
• Progress callbacks report bytes written and total length for UI updates (react-native-client API).
• Resumable downloads validate Content-Range before appending partial file data (react-native-client docs).
• Android background mode uses a foreground service; iOS uses a background URLSession path (react-native-client docs).

Working Examples

import { downloadFile, documentDirectoryPath } from 'react-native-client'

const result = await downloadFile({
fromUrl: 'https://example.com/model.gguf',
toFile: `${documentDirectoryPath}/model.gguf`,
})
console.log(result.statusCode, result.bytesWritten)

await downloadFile({
fromUrl: 'https://example.com/large-file.bin',
toFile: `${documentDirectoryPath}/large-file.bin`,
begin: (statusCode, contentLength) => {
console.log('started', statusCode, contentLength)
},
onProgress: (bytesWritten, contentLength) => {
if (contentLength > 0) {
console.log(`${Math.round((bytesWritten / contentLength) * 100)}%`)
}
},
})

Shows resumable background download and how to resume after app relaunch using the same request with resumable : true.

await downloadFile({
fromUrl: 'https://example.com/model.gguf',
toFile: `${documentDirectoryPath}/model.gguf`,
resumable: true,
background: true,
connectionTimeout: 30000,
readTimeout: 30000,
onProgress: (bytesWritten, contentLength) => {
console.log(bytesWritten, contentLength)
n},
n})
n
// To resume after app relaunch:
nconst modelPath = `${documentDirectoryPath}/model.gguf`
nawait downloadFile({
nfromUrl: modelUrl,
snapToFile: modelPath,
snapresumable: true,
snapbackground: true,
snap})
snap```
snapconst modelPath = `${documentDirectoryPath}/model.gguf`
snapawait downloadFile({
snapfromUrl: modelUrl,
snaptoFile: modelPath,
snapresumable: true,
snapbackground: true,
snap})

Practical Applications

• Use Case : Orb(offline AI app) downloads local models reliably despite network drops or force - closes . Pitfall : Using standard fetch for large files causes restarts on failure , wasting time and bandwidth .
• Use Case : Media packs , offline datasets , or cache warmups in React Native apps needing direct -to - disk streaming . Pitfall : Buffering entire file in JS memory leads to crashes on mobile devices with limited RAM .

References:

• https://github.com/zraisan/react -native -client
• https://www.npmjs.com/package/react -native -client
• https://play.google.com/store/apps/details?id=com.falaq.orb