Production build (expo) iOS app hangs when enabling session replay

[Crismon96]

What React Native libraries do you use?

React Native without Frameworks, Expo Application Services (EAS)

Are you using sentry.io or on-premise?

sentry.io (SaS)

@sentry/react-native SDK Version

7.1.0

How does your development environment look like?

info Fetching system and libraries information...
System:
  OS: macOS 15.3.2
  CPU: (8) arm64 Apple M2
  Memory: 310.22 MB / 16.00 GB
  Shell:
    version: 3.2.57
    path: /bin/bash
Binaries:
  Node:
    version: 20.13.1
    path: /private/var/folders/77/xk_dk18j35d3qlpn53s8z7dw0000gn/T/xfs-ed70aa84/node
  Yarn:
    version: 3.5.1
    path: /private/var/folders/77/xk_dk18j35d3qlpn53s8z7dw0000gn/T/xfs-ed70aa84/yarn
  npm:
    version: 10.5.2
    path: ~/.nvm/versions/node/v20.13.1/bin/npm
  Watchman:
    version: 2025.08.25.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.16.2
    path: /usr/local/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 24.5
      - iOS 18.5
      - macOS 15.5
      - tvOS 18.5
      - visionOS 2.5
      - watchOS 11.5
  Android SDK: Not Found
IDEs:
  Android Studio: 2025.1 AI-251.26094.121.2513.14007798
  Xcode:
    version: 16.4/16F6
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.16
    path: /usr/bin/javac
  Ruby:
    version: 3.4.5
    path: /opt/homebrew/opt/ruby/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 20.0.2
    wanted: ^20.0.2
  react:
    installed: 19.0.0
    wanted: 19.0.0
  react-native:
    installed: 0.79.5
    wanted: 0.79.5
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Sentry.init()

Sentry.init({
  dsn: 'https://<redacted>.ingest.us.sentry.io/<projectid>',
  sendDefaultPii: true,
  debug: true,
  environment: 'production',

Steps to Reproduce

1. I set up Sentry via the wizzard. It worked perfectly and firing an event I could see it on the sentry platform.
2. A local build with metro works well e.g.: expo run:ios. I can still navigate the app and fire events.
3. A production build via EAS on Testflight does not work at all, after the splashscreen the app just hangs. I have isolated that the commit of adding Sentry to the app caused the crash (only the setup in the commit is done and afterwards it doesnt work anymore).

I have put my git diff of that commit here:

clean_diff.txt

I tried to get device logs but the LLM says there are only logs of the app starting up, no logs of Sentry initializing even though debug is set to true.

Expected Result

The app on production should behave like the app on a local metro build. The app should start up with Sentry initialized

Actual Result

App just hangs after the splash screen. No real logs of other possibilities of interaction.

[linear]

RN-340 Development build (expo) works great - app hangs on prod build

[stefanosiano]

Hi @Crismon96, thanks for the report!
We're going to look into this and get back to you!
In the meantime, can you tell us what happens if you build the release app locally, via npx expo run:ios --configuration Release?

[Crismon96]

Thanks this helped to debug it. When I built it locally it got stuck at [apollon] Setting up session replay, the UI was not interactive at this moment.
When I disabled session replays it worked. I am now doing another eas prod build.

It would be great to get session replay working again. Can I provide you any input to help you with that?

[stefanosiano]

@Crismon96 Glad we narrowed down the issue to session replay!
@antonis can you have a look into it?