[bug]: Network request failed on Expo SDK 55 / React Native 0.83 — `onBeforeUploadBegin` never called

### Provide environment information

```bash
el_badi_dev@ELs-MacBook-Air birinia % npx envinfo --system --binaries --browsers --npmPackages "typescript,uploadthing,@uploadthing/react,@uploadthing/solid"
Need to install the following packages:
envinfo@7.21.0
Ok to proceed? (y) y


  System:
    OS: macOS 26.2
    CPU: (8) arm64 Apple M1
    Memory: 219.23 MB / 8.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 24.4.1 - /Users/el_badi_dev/.nvm/versions/node/v24.4.1/bin/node
    npm: 11.4.2 - /Users/el_badi_dev/.nvm/versions/node/v24.4.1/bin/npm
    pnpm: 10.12.1 - /opt/homebrew/bin/pnpm
    bun: 1.0.35 - /opt/homebrew/bin/bun
    Watchman: 2025.09.15.00 - /opt/homebrew/bin/watchman
  Browsers:
    Chrome: 146.0.7680.81
    Edge: 146.0.3856.62
    Safari: 26.2
  npmPackages:
    typescript: ~5.9.2 => 5.9.3 
    uploadthing: ^7.7.3 => 7.7.3 

el_badi_dev@ELs-MacBook-Air birinia %
```

### Describe the bug

<html><head></head><body><h1>🐛 [expo] Network request failed on Expo SDK 55 / React Native 0.83 — <code>onBeforeUploadBegin</code> never called</h1>
<h2>Description</h2>
<p>After upgrading from <strong>Expo SDK 53 (RN 0.79)</strong> to <strong>Expo SDK 55 (RN 0.83)</strong>, all uploads fail immediately with a <code>Network request failed</code> error. The crash happens before <code>onBeforeUploadBegin</code> is ever called, meaning the failure occurs during the initial presigned URL request — before the upload pipeline even starts.</p>
<p>The same codebase, same uploadthing versions, same backend — works perfectly on SDK 53.</p>
<h2>Error</h2>
<pre><code>ERROR [Error: Uncaught (in promise, id: 0) TypeError: Network request failed]
Code: fetch.umd.js
  565 |       xhr.onerror = function() {
  566 |         setTimeout(function() {
&gt; 567 |           reject(new TypeError('Network request failed'));
      |                               ^
  568 |         }, 0);
  569 |       };

Call Stack:
  setTimeout$argument_0 (node_modules/whatwg-fetch/dist/fetch.umd.js:567:31)
</code></pre>
<h2>Reproduction</h2>
<ol>
<li>Working project on Expo SDK 53 / RN 0.79 with <code>@uploadthing/expo</code></li>
<li>Upgrade to Expo SDK 55 / RN 0.83 (New Architecture mandatory, no opt-out)</li>
<li>Trigger <code>openImagePicker</code></li>
<li><code>onBeforeUploadBegin</code> is never called — crash happens before it</li>
</ol>
<h2>Environment</h2>

  | SDK 53 (working) | SDK 55 (broken)
-- | -- | --
expo | ^53.0.20 | ^55.0.6
react-native | 0.79.5 | 0.83.2
@uploadthing/expo | 7.2.5 | 7.2.6
uploadthing | 7.7.3 | 7.7.4
expo-image-picker | ~16.1.4 | ~55.0.12
Architecture | Old (opt-in new) | New Architecture only


<p><strong>Backend:</strong> Convex HTTP action (<code>https://xxx.convex.site</code>)<br>
<strong>Platform:</strong> Android (physical device), both WiFi and mobile data</p>
<h2>What was tried</h2>
<ul>
<li>✅ <code>@bacons/text-decoder</code> polyfill</li>
<li>✅ <code>expo/fetch</code> polyfill via <code>polyfillGlobal</code></li>
<li>✅ Blocking <code>whatwg-fetch</code> in metro <code>resolveRequest</code></li>
<li>✅ Blocking specifically when origin is <code>Libraries/Network/fetch.js</code></li>
<li>✅ Downgrading <code>expo-image-picker</code> and <code>expo-document-picker</code> to SDK 53 versions</li>
<li>✅ Simplifying <code>onBeforeUploadBegin</code> to just pass the file through unchanged</li>
<li>✅ Removing <code>react-native-compressor</code> entirely</li>
<li>✅ Verified <code>EXPO_PUBLIC_SERVER_URL</code> is correct (<code>https://xxx.convex.site</code>)</li>
</ul>
<h2>Key finding</h2>
<p><code>react-native/Libraries/Network/fetch.js</code> does <code>require('whatwg-fetch')</code> in both RN 0.79 and RN 0.83 — so this is not a new change. The <code>whatwg-fetch</code> polyfill was present and working in SDK 53, but causes <code>Network request failed</code> in SDK 55 / RN 0.83 New Architecture (Bridgeless mode).</p>
<pre><code class="language-js">// node_modules/react-native/Libraries/Network/fetch.js
'use strict';
require('whatwg-fetch'); // &lt;-- present in both RN 0.79 and RN 0.83
export const fetch = global.fetch;
...
</code></pre>
<p>This suggests the issue is specifically with how <strong>Bridgeless / New Architecture in RN 0.83</strong> handles XHR-based requests from <code>whatwg-fetch</code> when uploadthing makes the initial presigned URL fetch.</p>
<h2>Question</h2>
<p>Is <code>@uploadthing/expo</code> tested against Expo SDK 55 / RN 0.83 with New Architecture (Bridgeless)? Is there a known workaround or fix in progress?</p></body></html>

### Link to reproduction

https//:google.com

### To reproduce

## Steps to Reproduce

1. Set up a React Native / Expo project using **Expo SDK 55** (React Native 0.83, New Architecture mandatory)
2. Install uploadthing packages:
   ```bash
   npm install uploadthing @uploadthing/expo expo-image-picker expo-document-picker
   ```
3. Set up a Convex HTTP action as the uploadthing backend and set `EXPO_PUBLIC_SERVER_URL=https://xxx.convex.site`
4. Generate helpers in `uploadthing.ts`:
   ```ts
   import { generateReactNativeHelpers } from "@uploadthing/expo";
   export const { useImageUploader } = generateReactNativeHelpers({
     url: process.env.EXPO_PUBLIC_SERVER_URL,
   });
   ```
5. Use `useImageUploader` in a component and call `openImagePicker`
6. Add a `console.log` inside `onBeforeUploadBegin` to verify it is called
7. Run on a physical Android device and trigger the image picker
8. **Expected:** `onBeforeUploadBegin` is called, upload proceeds
9. **Actual:** App crashes with `TypeError: Network request failed` from `whatwg-fetch/dist/fetch.umd.js:567` — `onBeforeUploadBegin` is never reached

### Additional information

# Additional Context — Uploadthing Implementation Files

## `uploadthing.ts` (client helper setup)

```ts
import { generateReactNativeHelpers } from "@uploadthing/expo";
import { OurFileRouter } from "~/convex/uploadthing/index";

export const { useImageUploader, useDocumentUploader } =
  generateReactNativeHelpers<OurFileRouter>({
    /**
     * Your server url.
     * @default process.env.EXPO_PUBLIC_SERVER_URL
     * @remarks In dev we will also try to use Expo.debuggerHost
     */
    url: process.env.EXPO_PUBLIC_SERVER_URL,
  });
```

> **Note:** Backend is a **Convex HTTP action**, not Expo API routes. `EXPO_PUBLIC_SERVER_URL` is set to `https://xxx.convex.site`.

---

## `photo-picker.tsx` (upload component)

```tsx
import { useAuthToken } from "@convex-dev/auth/react";
import { openSettings } from "expo-linking";
import React from "react";
import { Alert } from "react-native";
import { PhotoIcon } from "react-native-heroicons/outline";
import { useImageUploader } from "~/src/lib/uploadthing";
import { Button } from "../ui/button";
import { useTheme } from "~/src/hooks/use-theme";

interface PhotoPickerProps {
  onImageSelected: (localUri: string) => string;
  onUploadComplete: (imageId: string, uploadedUrl: string) => void;
  onUploadError: (imageId: string, error: string) => void;
}

const PhotoPicker = ({
  onImageSelected,
  onUploadComplete,
  onUploadError,
}: PhotoPickerProps) => {
  const { theme } = useTheme();
  const token = useAuthToken();

  let currentImageId: string | null = null;

  const { openImagePicker } = useImageUploader("imageUploader", {
    headers: (): Record<string, string> => {
      if (!token) return {};
      return { Authorization: `Bearer ${token}` };
    },

    onClientUploadComplete: async (e) => {
      if (e[0].ufsUrl && e[0].customId && currentImageId) {
        const urlParts = e[0].ufsUrl.split("/");
        urlParts.pop();
        const baseUrl = urlParts.join("/");
        const imageUrl = `${baseUrl}/${e[0].customId}`;
        onUploadComplete(currentImageId, imageUrl);
        currentImageId = null;
      }
    },

    // ⚠️ This callback is NEVER reached — crash happens before it
    onBeforeUploadBegin: async (files: any[]) => {
      const file = files[0];
      currentImageId = onImageSelected(file.uri);
      return [file];
    },

    onUploadError: (error) => {
      if (currentImageId) {
        onUploadError(currentImageId, error.message || "فشل في رفع الصورة");
        currentImageId = null;
      }
      Alert.alert("خطأ في الرفع", error.message || "فشل في رفع الصورة");
    },
  });

  const handlePress = () => {
    openImagePicker({
      source: "library",
      onInsufficientPermissions: () => {
        Alert.alert(
          "لا توجد صلاحيات",
          "تحتاج إلى منح صلاحية للوصول إلى الصور لاستخدام هذه الميزة",
          [{ text: "إلغاء" }, { text: "فتح الإعدادات", onPress: openSettings }]
        );
      },
    });
  };

  return (
    <Button
      onPress={handlePress}
      variant="outline"
      className="w-20 h-20 rounded-xl border-2 border-dashed border-gray-300 bg-gray-50"
    >
      <PhotoIcon size={24} color={theme.foreground} />
    </Button>
  );
};

export default PhotoPicker;
```

---

## Key observations

- `onBeforeUploadBegin` is **never called** — confirmed via console log
- The crash is in `whatwg-fetch/dist/fetch.umd.js` at the XHR `onerror` handler
- This means the failure is in the **initial presigned URL request** to the Convex backend, before the upload pipeline starts
- The same code works on SDK 53 / RN 0.79 with no changes

### 👨‍👧‍👦 Contributing

- [ ] 🙋‍♂️ Yes, I'd be down to file a PR fixing this bug!

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

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[bug]: Network request failed on Expo SDK 55 / React Native 0.83 — `onBeforeUploadBegin` never called #1273

Provide environment information

Describe the bug

🐛 [expo] Network request failed on Expo SDK 55 / React Native 0.83 — `onBeforeUploadBegin` never called

Description

Error

Reproduction

Environment

What was tried

Key finding

Question

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To reproduce

Steps to Reproduce

Additional information

Additional Context — Uploadthing Implementation Files

`uploadthing.ts` (client helper setup)

`photo-picker.tsx` (upload component)

Key observations

👨‍👧‍👦 Contributing

Code of Conduct

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	SDK 53 (working)	SDK 55 (broken)
expo	^53.0.20	^55.0.6
react-native	0.79.5	0.83.2
@uploadthing/expo	7.2.5	7.2.6
uploadthing	7.7.3	7.7.4
expo-image-picker	~16.1.4	~55.0.12
Architecture	Old (opt-in new)	New Architecture only

[bug]: Network request failed on Expo SDK 55 / React Native 0.83 — onBeforeUploadBegin never called #1273

Description

Provide environment information

Describe the bug

🐛 [expo] Network request failed on Expo SDK 55 / React Native 0.83 — onBeforeUploadBegin never called

Description

Error

Reproduction

Environment

What was tried

Key finding

Question

Link to reproduction

To reproduce

Steps to Reproduce

Additional information

Additional Context — Uploadthing Implementation Files

uploadthing.ts (client helper setup)

photo-picker.tsx (upload component)

Key observations

👨‍👧‍👦 Contributing

Code of Conduct

Metadata

Metadata

Assignees

Labels

Type

Projects

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Development

Issue actions

[bug]: Network request failed on Expo SDK 55 / React Native 0.83 — `onBeforeUploadBegin` never called #1273

🐛 [expo] Network request failed on Expo SDK 55 / React Native 0.83 — `onBeforeUploadBegin` never called

`uploadthing.ts` (client helper setup)

`photo-picker.tsx` (upload component)