feat: v8: Capture app start errors before JS #5582

antonis · 2026-01-26T16:42:07Z

📢 Type of change

Bugfix
New feature
Enhancement
Refactoring

📜 Description

Follow up to #4472 (v6) > #5470 (v7) targeting v8 #5501

Capture App Start errors and crashes by initializing Sentry from sentry.options.json (#4472)

Create sentry.options.json in the React Native project root and set options the same as you currently have in Sentry.init in JS.

{
    "dsn": "https://[email protected]/value",
}

Initialize Sentry on the native layers by newly provided native methods.

import io.sentry.react.RNSentrySDK

class MainApplication : Application(), ReactApplication {
    override fun onCreate() {
        super.onCreate()
        RNSentrySDK.init(this)
    }
}

#import <RNSentry/RNSentry.h>

@implementation AppDelegate
- (BOOL)application:(UIApplication *)application
    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [RNSentrySDK start];
    return [super application:application didFinishLaunchingWithOptions:launchOptions];
}
@end

Add RNSentrySDK APIs support to @sentry/react-native/expo plugin (#4633)
- Adds useNativeInit option to automatically initialize Sentry natively before JavaScript loads, enabling capture of app start errors
```
{
  "expo": {
    "plugins": [
      [
        "@sentry/react-native/expo",
        {
          "useNativeInit": true
        }
      ]
    ]
  }
}
```

Changes

Load optionsFile into the JS bundle during Metro bundle process (#4476)
Add experimental version of startWithConfigureOptions for Apple platforms (#4444)
Add experimental version of init with optional OptionsConfiguration<SentryAndroidOptions> for Android (#4451)
Add initialization using sentry.options.json for Apple platforms (#4447)
Add initialization using sentry.options.json for Android (#4451)
Merge options from file with Sentry.init options in JS (#4510)

Internal

Extract iOS native initialization to standalone structures (#4442)
Extract Android native initialization to standalone structures (#4445)

Note

The feature the feature should be 100% backwards compatible and opt-in. Users who don't create sentry.options.json or call RNSentrySDK.start()/init() will experience zero changes to their existing Sentry implementation. The traditional JS-only initialization path remains fully functional and is the default behavior.

📝 Documentation PR: getsentry/sentry-docs#16170

💡 Motivation and Context

Fixes #3608

Previously, React Native apps couldn't capture errors that occurred during app startup before JavaScript initialized, because Sentry was only initialized from JavaScript code (Sentry.init()). This meant crashes during:

Native module initialization
JavaScript bundle loading
Early React Native bridge setup

were never captured.

💚 How did you test it?

CI, Manually

📝 Checklist

I added tests to verify changes
No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled
I updated the docs if needed.
I updated the wizard if needed.
All tests passing
No breaking changes

🔮 Next steps

#skip-changelog

…ructures (#4445) * Extract Android SDK Init * Update tests * Adds changelog * Fix lint issues * Rename RNSentryStart instance for clarity * Converts RNSentryStart to utility class * Update CHANGELOG.md --------- Co-authored-by: Krystof Woldrich <[email protected]>

…platforms (#4444)

* Convert json object to writable map * Make class/methods package-private(default)

…4451)

)

…4533)

…mple (#4535)

)

#4561)

…4595)

- Resolved merge conflicts across iOS, Android, and JavaScript/TypeScript code - Updated iOS implementation to use RNSentryStart API - Fixed Android compilation errors for Sentry Android SDK v7 compatibility - Removed deprecated API calls (setEnableTracing, getPackages, getIntegrations) - Updated Gradle build scripts and resolved conflict markers - All builds verified: iOS, Android, and Expo sample apps compile successfully

github-actions · 2026-01-26T16:42:29Z

Semver Impact of This PR

⚪ None (no version bump detected)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

This PR will not appear in the changelog.

_{🤖 This preview updates automatically when you update the PR.}

github-actions · 2026-01-26T16:42:46Z

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against ed126ab

github-actions · 2026-01-26T17:00:32Z

Android (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	362.50 ms	390.44 ms	27.94 ms
Size	43.94 MiB	49.22 MiB	5.29 MiB

Baseline results on branch: v8

Startup times

Revision	Plain	With Sentry	Diff
`b4fa5b4`+dirty	382.09 ms	398.28 ms	16.19 ms
`12fba4a`+dirty	456.57 ms	462.90 ms	6.32 ms
`fa0d109`+dirty	413.71 ms	434.22 ms	20.51 ms
`d6aa223`+dirty	436.98 ms	466.42 ms	29.44 ms
`206e87e`+dirty	416.94 ms	440.98 ms	24.04 ms
`bc8a1ed`+dirty	396.10 ms	426.80 ms	30.69 ms

App size

Revision	Plain	With Sentry	Diff
`b4fa5b4`+dirty	43.94 MiB	48.91 MiB	4.97 MiB
`12fba4a`+dirty	43.94 MiB	49.22 MiB	5.29 MiB
`fa0d109`+dirty	43.94 MiB	49.22 MiB	5.29 MiB
`d6aa223`+dirty	43.94 MiB	49.38 MiB	5.44 MiB
`206e87e`+dirty	43.94 MiB	49.22 MiB	5.29 MiB
`bc8a1ed`+dirty	43.94 MiB	48.91 MiB	4.97 MiB

Previous results on branch: antonis/capture-app-start-errors-v8

Startup times

Revision	Plain	With Sentry	Diff
`b4df5a0`+dirty	364.57 ms	389.29 ms	24.71 ms
`88812b1`+dirty	425.90 ms	435.25 ms	9.35 ms
`82de722`+dirty	398.52 ms	422.70 ms	24.18 ms

App size

Revision	Plain	With Sentry	Diff
`b4df5a0`+dirty	43.94 MiB	49.22 MiB	5.29 MiB
`88812b1`+dirty	43.94 MiB	49.22 MiB	5.29 MiB
`82de722`+dirty	43.94 MiB	49.22 MiB	5.29 MiB

github-actions · 2026-01-26T17:02:01Z

Android (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	486.30 ms	504.74 ms	18.44 ms
Size	43.75 MiB	48.40 MiB	4.64 MiB

Baseline results on branch: v8

Startup times

Revision	Plain	With Sentry	Diff
`b4fa5b4`+dirty	449.55 ms	481.50 ms	31.95 ms
`12fba4a`+dirty	483.60 ms	514.49 ms	30.89 ms
`fa0d109`+dirty	429.60 ms	452.50 ms	22.90 ms
`d6aa223`+dirty	543.40 ms	564.24 ms	20.84 ms
`206e87e`+dirty	464.80 ms	504.68 ms	39.88 ms
`bc8a1ed`+dirty	442.18 ms	476.27 ms	34.08 ms

App size

Revision	Plain	With Sentry	Diff
`b4fa5b4`+dirty	43.75 MiB	48.08 MiB	4.33 MiB
`12fba4a`+dirty	43.75 MiB	48.40 MiB	4.64 MiB
`fa0d109`+dirty	43.75 MiB	48.40 MiB	4.64 MiB
`d6aa223`+dirty	43.75 MiB	48.55 MiB	4.80 MiB
`206e87e`+dirty	43.75 MiB	48.40 MiB	4.64 MiB
`bc8a1ed`+dirty	43.75 MiB	48.08 MiB	4.33 MiB

Previous results on branch: antonis/capture-app-start-errors-v8

Startup times

Revision	Plain	With Sentry	Diff
`b4df5a0`+dirty	405.80 ms	412.56 ms	6.77 ms
`88812b1`+dirty	428.04 ms	462.22 ms	34.18 ms
`82de722`+dirty	425.13 ms	457.02 ms	31.89 ms

App size

Revision	Plain	With Sentry	Diff
`b4df5a0`+dirty	43.75 MiB	48.40 MiB	4.65 MiB
`88812b1`+dirty	43.75 MiB	48.40 MiB	4.64 MiB
`82de722`+dirty	43.75 MiB	48.40 MiB	4.64 MiB

github-actions · 2026-01-26T17:06:10Z

iOS (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1212.64 ms	1208.47 ms	-4.18 ms
Size	3.38 MiB	4.67 MiB	1.29 MiB

Baseline results on branch: v8

Startup times

Revision	Plain	With Sentry	Diff
`206e87e`+dirty	1197.12 ms	1204.25 ms	7.13 ms
`b4fa5b4`+dirty	1213.59 ms	1211.26 ms	-2.33 ms
`d6aa223`+dirty	1216.76 ms	1213.40 ms	-3.37 ms
`12fba4a`+dirty	1209.43 ms	1217.08 ms	7.65 ms
`bc8a1ed`+dirty	1198.66 ms	1200.60 ms	1.94 ms
`fa0d109`+dirty	1206.81 ms	1205.38 ms	-1.43 ms

App size

Revision	Plain	With Sentry	Diff
`206e87e`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`b4fa5b4`+dirty	3.44 MiB	4.66 MiB	1.22 MiB
`d6aa223`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`12fba4a`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`bc8a1ed`+dirty	3.44 MiB	4.66 MiB	1.22 MiB
`fa0d109`+dirty	3.38 MiB	4.67 MiB	1.29 MiB

Previous results on branch: antonis/capture-app-start-errors-v8

Startup times

Revision	Plain	With Sentry	Diff
`88812b1`+dirty	1210.98 ms	1215.22 ms	4.24 ms
`82de722`+dirty	1210.87 ms	1217.00 ms	6.13 ms
`b4df5a0`+dirty	1217.06 ms	1221.61 ms	4.55 ms

App size

Revision	Plain	With Sentry	Diff
`88812b1`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`82de722`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`b4df5a0`+dirty	3.38 MiB	4.67 MiB	1.29 MiB

github-actions · 2026-01-26T17:13:33Z

iOS (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1212.24 ms	1214.44 ms	2.20 ms
Size	3.38 MiB	4.67 MiB	1.29 MiB

Baseline results on branch: v8

Startup times

Revision	Plain	With Sentry	Diff
`206e87e`+dirty	1184.11 ms	1183.19 ms	-0.92 ms
`b4fa5b4`+dirty	1203.83 ms	1207.13 ms	3.30 ms
`d6aa223`+dirty	1192.33 ms	1208.17 ms	15.84 ms
`12fba4a`+dirty	1214.20 ms	1223.30 ms	9.09 ms
`bc8a1ed`+dirty	1194.70 ms	1201.18 ms	6.48 ms
`fa0d109`+dirty	1216.02 ms	1220.67 ms	4.65 ms

App size

Revision	Plain	With Sentry	Diff
`206e87e`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`b4fa5b4`+dirty	3.44 MiB	4.66 MiB	1.22 MiB
`d6aa223`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`12fba4a`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`bc8a1ed`+dirty	3.44 MiB	4.66 MiB	1.22 MiB
`fa0d109`+dirty	3.38 MiB	4.67 MiB	1.29 MiB

Previous results on branch: antonis/capture-app-start-errors-v8

Startup times

Revision	Plain	With Sentry	Diff
`88812b1`+dirty	1216.63 ms	1215.55 ms	-1.08 ms
`82de722`+dirty	1213.09 ms	1208.90 ms	-4.19 ms
`b4df5a0`+dirty	1213.04 ms	1218.59 ms	5.55 ms

App size

Revision	Plain	With Sentry	Diff
`88812b1`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`82de722`+dirty	3.38 MiB	4.67 MiB	1.29 MiB
`b4df5a0`+dirty	3.38 MiB	4.67 MiB	1.29 MiB

antonis · 2026-01-27T09:37:47Z

@sentry review

lucas-zimerman · 2026-01-27T11:22:17Z

No noticeable impact on iOS, the app size increase by adding sentry on java is interesting though, but no extra impact from this PR.

antonis · 2026-01-27T11:25:14Z

No noticeable impact on iOS, the app size increase by adding sentry on java is interesting though, but no extra impact from this PR.

That's a good catch @lucas-zimerman 🤔

I wonder if this has to do with the Gradle Plugin bump #5578 on the v8 base branch #5501

lucas-zimerman · 2026-01-27T11:28:42Z

CHANGELOG.md

+        [
+          "@sentry/react-native/expo",
+          {
+            "useNativeInit": true


Q: Do all sentry options work here? we should document this feature.

This is the only added option in the plugin. I've started a documentation PR in getsentry/sentry-docs#16170

antonis · 2026-01-27T12:04:27Z

No noticeable impact on iOS, the app size increase by adding sentry on java is interesting though, but no extra impact from this PR.

That's a good catch @lucas-zimerman 🤔

I wonder if this has to do with the Gradle Plugin bump #5578 on the v8 base branch #5501

Looking at it again I think the With Sentry sizes are the same with the base branch 48.40 MiB (legacy), 49.22 MiB (new)

lucas-zimerman

After a complete PR review and also loads of tokens, I can really say, LGTM!

packages/core/scripts/sentry-xcode.sh

packages/core/ios/RNSentry.mm

Co-authored-by: LucasZF <[email protected]>

# Conflicts: # CHANGELOG.md

antonis · 2026-01-27T15:28:09Z

@sentry review

packages/core/android/src/main/java/io/sentry/react/RNSentryStart.java

* fix(android): Fix ConcurrentModificationException when disabling native crash handling When enableNativeCrashHandling is set to false, the code was iterating over the integrations list with a for-each loop while calling remove() directly, which causes a ConcurrentModificationException at runtime. Fixed by using Java 8's removeIf() method which safely handles iteration and removal in a single operation. This is more concise and follows modern Java best practices. Added unit tests to verify the fix and ensure integrations are properly removed without throwing exceptions. Co-Authored-By: Claude Sonnet 4.5 <[email protected]> * Lint fix --------- Co-authored-by: Claude Sonnet 4.5 <[email protected]>

packages/core/android/src/main/java/io/sentry/react/RNSentryStart.java

…carUrl The code attempted to read defaultSidecarUrl without checking if the key exists in the options map. This caused a NoSuchKeyException crash during startup when spotlight was set to true in sentry.options.json without providing defaultSidecarUrl. Added key existence check to match iOS implementation behavior and prevent the crash while maintaining backward compatibility. Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

krystofwoldrich and others added 30 commits January 21, 2025 17:22

ref(ios): Extract Cocoa SDK init into standalone file (#4442)

00e9040

Merge branch 'main' into capture-app-start-errors

4c0b8f4

feat(experimental): Add native startWithConfigureOptions for Apple …

7144a64

…platforms (#4444)

feat: Read sentry.options.json during cocoa init (#4447)

7850677

Adds utility class for converting JsonObject to WritableMap (#4479)

1e5dbde

* Convert json object to writable map * Make class/methods package-private(default)

feat: Automatically load sentry.options.json file (#4476)

22a5f81

feat(experimental): Initialize Android SDK from json configuration (#…

a1cb36d

…4451)

Merge branch 'main' into capture-app-start-errors

95c36ef

misc: Add sentry.options.json example to the changelog (#4509)

14fe05d

feat(init): Load options from sentry.options.json in JS (#4510)

15a7e6d

release: 6.7.0-alpha.0

b9ec093

Merge branch 'release/6.7.0-alpha.0' into capture-app-start-errors

dbdd4b5

misc(sample): Change RN Sample to use native file init by default (#4522

b947d7f

)

chore(sample-rn): Remove duplicate init options from code (#4532)

6b08b9a

chore(sample-rn): Always use fhe file option (including auto init) (#…

a7ffa1f

…4533)

internal(sample-rn): Add Detox for integration/e2e tests of the rn sa…

28cf7b4

…mple (#4535)

internal(sample-rn): Add header and message envelope tests (#4536)

cf00d4d

Merge remote-tracking branch 'origin/main' into capture-app-start-errors

b754aa3

fix(sample-e2e): Fix type errors missing sentry/core and afterAll (#4564

0bf6636

)

Merge remote-tracking branch 'origin/main' into capture-app-start-errors

0f5cd7d

chore(samples): Add package scripts for native builds, dsn and testing (

e935360

#4561)

Merge branch 'main' into capture-app-start-errors

952dd05

test(e2e): Verify captured Errors Screen transaction (#4584)

ae342a3

test(e2e): Add auto init from JS tests (#4588)

770f9fb

test(e2e): Add app start crash test for iOS (#4593)

cbb85b2

test(e2e): Avoid race conditions when waiting for captured message (#…

b4ee16b

…4595)

chore(sample-e2e): Move Detox related files to e2e-detox dir

ee11f58

Merge branch 'main' into capture-app-start-errors

588ba6d

antonis added the ready-to-merge Triggers the full CI test suite label Jan 26, 2026

antonis changed the title ~~feat: v7: Capture app start errors before JS~~ feat: v8: Capture app start errors before JS Jan 26, 2026

antonis mentioned this pull request Jan 26, 2026

[React-Native]: v8 #5501

Draft

Fix native ios tests

e6505b7

antonis mentioned this pull request Jan 27, 2026

test(e2e): Add auto init from JS tests for Android #5583

Open

10 tasks

antonis marked this pull request as ready for review January 27, 2026 09:41

antonis requested review from alwx and lucas-zimerman as code owners January 27, 2026 09:41

This was referenced Jan 27, 2026

feat: v7: Capture app start errors before JS #5470

Closed

RN: Capture Startup Crashes getsentry/sentry-docs#16170

Open

lucas-zimerman reviewed Jan 27, 2026

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antonis and others added 2 commits January 27, 2026 14:05

Mark area

f4584c5

Co-authored-by: LucasZF <[email protected]>

Merge branch 'v8' into antonis/capture-app-start-errors-v8

44282b5

# Conflicts: # CHANGELOG.md

sentry bot reviewed Jan 27, 2026

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antonis mentioned this pull request Jan 27, 2026

fix(android): Fix ConcurrentModificationException #5588

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📢 Type of change

📜 Description

Changes

Internal

Note

💡 Motivation and Context

💚 How did you test it?

📝 Checklist

🔮 Next steps

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Android (new) Performance metrics 🚀

Baseline results on branch: v8

Startup times

App size

Previous results on branch: antonis/capture-app-start-errors-v8

Startup times

App size

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Android (legacy) Performance metrics 🚀

Baseline results on branch: v8

Startup times

App size

Previous results on branch: antonis/capture-app-start-errors-v8

Startup times

App size

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iOS (new) Performance metrics 🚀

Baseline results on branch: v8

Startup times

App size

Previous results on branch: antonis/capture-app-start-errors-v8

Startup times

App size

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iOS (legacy) Performance metrics 🚀

Baseline results on branch: v8

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App size

Previous results on branch: antonis/capture-app-start-errors-v8

Startup times

App size

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