Android: Network Error when sending FormData with file upload (Axios/Fetch) - React-Native 0/84

[emrektc70]

Description

When attempting to upload a file using FormData on Android, the request immediately fails with a generic Network Error (or TypeError: Network request failed with fetch). The same code works perfectly on iOS.

`export type CreateAgencyTimelineParams = {
agency?: Iri<API.AGENCIES>
/**
* Should be a File
*/
file?: any | undefined
status: Iri<API.TIMELINE_STATUSES>
comment: string
parent?: string | null
tags?: string[]
}

export function createAgencyTimeline(
params: CreateAgencyTimelineParams,
config?: ExtendedAxiosRequestConfig
) {
const form = new FormData()

form.append('agency', params.agency as string)
form.append('comment', params.comment)
form.append('status', params.status as string)

if (!!params.parent?.length) form.append('parent', params.parent as string)

if (params.file) {
    form.append('file', params.file)
}
if (params.tags && params.tags.length > 0) {
    params.tags.forEach(tag => form.append('tags[]', tag))
}

return (config?.instance ?? axios).post('/api/agency/timelines-simple', form, {
    ...(config ?? {}),
    transformRequest: data => {
        return data
    }
})

}`

Steps to reproduce

Pick a file using a library like react-native-image-picker or expo-image-picker on an Android Emulator or device.

Construct a FormData object and append a file using the standard React Native format:

JavaScript
const formData = new FormData();
formData.append('file', {
uri: file.uri, // Ensure it starts with file:///
type: 'image/jpeg',
name: 'photo.jpg',
});
Execute a POST request using Axios (with a custom instance) or Fetch to a remote server.

Observe the result: On iOS, the request is successful. On Android, it immediately throws a Network Error before even hitting the server (no outgoing traffic visible in server logs).

React Native Version

0.84.0

Affected Platforms

Runtime - Android

Output of npx @react-native-community/cli info

info Fetching system and libraries information...
System:
  OS: macOS 26.3
  CPU: (12) arm64 Apple M4 Pro
  Memory: 2.43 GB / 24.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 24.13.0
    path: ~/.nvm/versions/node/v24.13.0/bin/node
  Yarn:
    version: 4.8.1
    path: ~/.nvm/versions/node/v24.13.0/bin/yarn
  npm:
    version: 8.19.4
    path: ~/Developer/studiosystems-monorepo/node_modules/.bin/npm
  Watchman:
    version: 2024.12.02.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.16.2
    path: /Users/emrekartici/.rbenv/shims/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 25.2
      - iOS 26.2
      - macOS 26.2
      - tvOS 26.2
      - visionOS 26.2
      - watchOS 26.2
  Android SDK:
    API Levels:
      - "33"
      - "34"
      - "35"
      - "36"
    Build Tools:
      - 34.0.0
      - 35.0.0
      - 36.0.0
    System Images:
      - android-34 | Google APIs ARM 64 v8a
      - android-35 | Google Play ARM 64 v8a
      - android-36 | Google Play ARM 64 v8a
    Android NDK: Not Found
IDEs:
  Android Studio: 2024.3 AI-243.26053.27.2432.13536105
  Xcode:
    version: 26.2/17C52
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 21.0.6
    path: /usr/bin/javac
  Ruby:
    version: 2.7.8
    path: /Users/emrekartici/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 20.1.0
    wanted: 20.1.0
  react:
    installed: 19.2.3
    wanted: 19.2.3
  react-native:
    installed: 0.84.0
    wanted: 0.84.0
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Stacktrace or Logs

Network error

MANDATORY Reproducer

/

Screenshots and Videos

No response

[react-native-bot]

Warning

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• For majority of bugs: send us a Pull Request with the RNTesterPlayground.js edited to reproduce your bug.
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• If your bug is build/upgrade related: a project using our Reproducer Template

You can read more about about it on our website: How to report a bug.

[priyaQB07]

@emrektc70
After doing some R&D on this, it doesn’t look like a FormData issue itself.

Since the exact same implementation works on iOS but fails immediately on Android (with Network Error / TypeError: Network request failed) and the request never reaches the server, this strongly suggests that Android is blocking the request at the native level before it is actually sent.

Since:

• The same implementation works perfectly on iOS
• The request fails immediately on Android
• No request reaches the server (no logs visible)
• The error is a generic Network Error / TypeError: Network request failed

This strongly suggests that Android is blocking the request at the native level before it is actually sent.

On Android (API 28+), cleartext HTTP traffic is blocked by default. If the API endpoint is:

The same code works correctly on iOS, but on Android the request fails immediately with:

• Network Error
• TypeError: Network request failed

Additionally:

• The request never reaches the backend
• No logs are generated on the server
• The failure happens instantly

When a request fails before leaving the device, it usually indicates that Android is blocking it at the native networking layer.

---

Likely Cause: Android Network Security Configuration

Starting from Android 9 (API 28+), cleartext (HTTP) traffic is blocked by default.

If the API endpoint is:

• Using HTTP instead of HTTPS
• Using HTTPS with an invalid or self-signed certificate
• Not properly configured in Android’s network_security_config.xml

Android will immediately reject the request with a generic network error.

For debugging purposes only (not recommended for production), you can temporarily allow cleartext traffic in AndroidManifest.xml:

<application
    android:usesCleartextTraffic="true"
    ...
/>