WebSocket.ping() on Android sends an empty binary frame instead of a protocol-level PING

[dekpient]

Description

WebSocket.ping() on Android sends an empty binary data frame (opcode 0x2) via OkHttp's
client.send(ByteString.EMPTY), instead of a real RFC 6455 PING control frame (opcode 0x9). On iOS,
ping() correctly sends a protocol-level ping via SocketRocket's sendPing:error:.

This breaks against WebSocket servers that reject binary frames (e.g. AWS API Gateway WebSocket APIs),
which close the connection with code 1003 UNSUPPORTED_DATA instead of responding with a pong.

The incorrect ping() that sends the empty frame is still present on the latest version (v0.86.2) of RN here: https://github.com/react/react-native/blob/v0.86.2/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/modules/websocket/WebSocketModule.kt#L327

    try {
      client.send(ByteString.EMPTY)
    } catch (e: Exception) {
      notifyWebSocketFailed(id, e.message)
    }

Steps to reproduce

1. Connect a WebSocket to a server that rejects binary frames (e.g. AWS API Gateway WS API).
2. Call webSocket.ping() on Android.
3. Observe the connection closes with 1003 UNSUPPORTED_DATA instead of receiving a pong.

React Native Version

0.77.3 (and still present in 0.86.2)

Affected Platforms

Runtime - Android

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

System:
  OS: macOS 26.5.2
  CPU: (12) arm64 Apple M4 Pro
  Memory: 348.30 MB / 24.00 GB
  Shell:
    version: "5.9"
    path: /opt/homebrew/bin/zsh
Binaries:
  Node:
    version: 20.19.4
    path: /Users/inging/.nodenv/versions/20.19.4/bin/node
  Yarn:
    version: 1.22.19
    path: /opt/homebrew/bin/yarn
  npm:
    version: 10.8.2
    path: /Users/inging/.nodenv/versions/20.19.4/bin/npm
  Watchman:
    version: 2025.05.19.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /Users/inging/.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: Not Found
IDEs:
  Android Studio: 2024.2 AI-242.23726.103.2422.12816248
  Xcode:
    version: 26.2/17C52
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.14
    path: /Users/inging/.jenv/shims/javac
  Ruby:
    version: 3.2.2
    path: /Users/inging/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 15.1.3
    wanted: 15.1.3
  react:
    installed: 18.3.1
    wanted: 18.3.1
  react-native:
    installed: 0.77.3
    wanted: 0.77.3
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: false
iOS:
  hermesEnabled: true
  newArchEnabled: false

Stacktrace or Logs

Logs from mitmproxy with a custom interceptor script:


<IP_REDACTED>:44604 -> WebSocket binary message -> <WSS_HOST_REDACTED>:443/
Error in WebSocket connection to <WSS_HOST_REDACTED>:443: WebSocket Error: UNSUPPORTED_DATA (reason: Binary is not supported)

MANDATORY Reproducer

https://gist.github.com/dekpient/4b611eb4efb58ecc1a881942f842a595

Screenshots and Videos

[react-native-bot]

Caution

Too old version: It looks like your issue or the example you provided uses a Too Old Version of React Native.

Due to the number of issues we receive, we're currently only accepting new issues against one of the supported versions. Please upgrade to latest and verify if the issue persists (alternatively, create a new project and repro the issue in it). If you cannot upgrade, please open your issue on StackOverflow to get further community support.

[react-native-bot]

Warning

Missing reproducer: We could not detect a reproducible example in your issue report. Reproducers are mandatory and we can accept only one of those as a valid reproducer:

• For majority of bugs: send us a Pull Request with the RNTesterPlayground.js edited to reproduce your bug.
• If your bug is UI related: a Snack
• 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.

[react-native-bot]

Caution

Too old version: It looks like your issue or the example you provided uses a Too Old Version of React Native.

Due to the number of issues we receive, we're currently only accepting new issues against one of the supported versions. Please upgrade to latest and verify if the issue persists (alternatively, create a new project and repro the issue in it). If you cannot upgrade, please open your issue on StackOverflow to get further community support.