Crashlytics setup in Firebase - Commands & Configuration

Introduction

Crashlytics helps you find and fix app crashes quickly. It collects crash reports from your app so you can improve its stability.

When you want to know why your app crashes on users' devices.

When you need detailed reports about errors in your app.

When you want to prioritize fixing bugs that affect many users.

When you want to monitor app health after releasing updates.

When you want automatic alerts for new or frequent crashes.

Config File - firebase.json

firebase.json

{
  "react-native": {
    "crashlytics_debug_enabled": true,
    "crashlytics_auto_collection_enabled": true
  }
}

This file configures Firebase Crashlytics for a React Native app.

crashlytics_debug_enabled: Enables crash reporting during development.

crashlytics_auto_collection_enabled: Automatically collects crash reports without extra code.

Commands

Log in to your Firebase account to access your projects and services.

Terminal

firebase login

Expected Output

✔  Success! Logged in as [e-mail]

Initialize Crashlytics in your Firebase project to set up necessary files and configurations.

Terminal

firebase init crashlytics

Expected Output

=== Crashlytics Setup ===

✔ Firebase Crashlytics has been initialized in your project.

Deploy the Crashlytics configuration to Firebase so it starts monitoring your app crashes.

Terminal

firebase deploy --only crashlytics

Expected Output

=== Deploying to 'your-project-id' ===

✔  Deploy complete!

Project Console: https://console.firebase.google.com/project/your-project-id/overview

→

--only - Deploy only the specified Firebase service, here Crashlytics.

List current crash issues reported by Crashlytics to verify it is collecting data.

Terminal

firebase crashlytics:issues:list

Expected Output

No crash issues found.

(Or a list of crash issues with IDs and descriptions)

Key Concept

If you remember nothing else from this pattern, remember: Crashlytics automatically collects crash reports after setup so you can fix app problems faster.

Common Mistakes

Not logging into Firebase CLI before initializing Crashlytics

The CLI commands fail because they need authentication to access your Firebase project.

Always run 'firebase login' first to authenticate.

Skipping the deploy step after initialization

Crashlytics settings won't apply until you deploy, so no crash data will be collected.

Run 'firebase deploy --only crashlytics' to apply your configuration.

Not enabling automatic crash collection in the config file

Crash reports won't be sent automatically, requiring manual code changes.

Set 'crashlytics_auto_collection_enabled' to true in firebase.json.

Summary

Log in to Firebase CLI to access your project.

Initialize Crashlytics to set up monitoring files.

Deploy Crashlytics configuration to start collecting crash reports.

Check crash issues to verify Crashlytics is working.

Practice

1. What is the primary purpose of Firebase Crashlytics in an app?

easy

A. To automatically detect and report app crashes

B. To store user data securely

C. To manage app user authentication

D. To optimize app performance speed

Solution

1. Step 1: Understand Crashlytics function

   Crashlytics is designed to catch app crashes and send reports automatically to Firebase Console.

2. Step 2: Compare with other Firebase features

   Other options like data storage, authentication, and performance are handled by different Firebase services.

3. Final Answer:

   To automatically detect and report app crashes -> Option A

4. Quick Check:

   Crashlytics = crash reporting [OK]

Hint: Crashlytics = crash reports, not data or auth [OK]

Common Mistakes:

• Confusing Crashlytics with Firebase Authentication
• Thinking Crashlytics manages user data
• Assuming Crashlytics improves app speed

2. Which of the following is the correct step to initialize Crashlytics in an Android app's onCreate() method?

easy

A. FirebaseCrashlytics.getInstance().setCrashlyticsCollectionEnabled(true);

B. Crashlytics.initializeCrashlytics();

C. FirebaseApp.initializeApp(this);

D. Crashlytics.startCrashlyticsSession();

Solution

1. Step 1: Identify correct Crashlytics initialization

   The official way to enable Crashlytics collection is calling FirebaseCrashlytics.getInstance().setCrashlyticsCollectionEnabled(true);.

2. Step 2: Check other options

   Crashlytics.initializeCrashlytics() and Crashlytics.startCrashlyticsSession() are not valid Firebase SDK methods. FirebaseApp.initializeApp(this); initializes Firebase but not Crashlytics specifically.

3. Final Answer:

   FirebaseCrashlytics.getInstance().setCrashlyticsCollectionEnabled(true); -> Option A

4. Quick Check:

   Enable Crashlytics with setCrashlyticsCollectionEnabled(true) [OK]

Hint: Use FirebaseCrashlytics.getInstance() to enable collection [OK]

Common Mistakes:

• Using non-existent Crashlytics methods
• Confusing FirebaseApp initialization with Crashlytics setup
• Forgetting to enable crash collection explicitly

3. Given this Android code snippet, what will happen when the app runs?

FirebaseCrashlytics crashlytics = FirebaseCrashlytics.getInstance();
crashlytics.log("User clicked button");
throw new RuntimeException("Test crash");

medium

A. The app logs the message but does not crash

B. The app ignores the exception and continues running

C. The app crashes silently without logging

D. The app logs the message and crashes, sending a report to Firebase

Solution

1. Step 1: Analyze the code behavior

   The code logs a message to Crashlytics and then throws a RuntimeException, which causes the app to crash.

2. Step 2: Understand Crashlytics reporting

   Crashlytics captures the log and crash, then sends the crash report to Firebase Console for analysis.

3. Final Answer:

   The app logs the message and crashes, sending a report to Firebase -> Option D

4. Quick Check:

   Crashlytics logs + crash = report sent [OK]

Hint: Throw exception after logging to test Crashlytics [OK]

Common Mistakes:

• Thinking the app won't crash after exception
• Assuming logs are not sent with crash
• Believing the app ignores exceptions

4. You added Crashlytics to your iOS app but no crash reports appear in Firebase Console after forcing a crash. What is the most likely mistake?

medium

A. Calling Crashlytics.crash() before initializing Firebase

B. Forgetting to enable Crashlytics in Firebase Console

C. Not calling FirebaseApp.configure() in application(_:didFinishLaunchingWithOptions:)

D. Using an unsupported iOS version

Solution

1. Step 1: Check Firebase initialization

   Calling FirebaseApp.configure() is required but usually done correctly if app runs.

2. Step 2: Verify Crashlytics enablement in Console

   Crashlytics must be enabled in Firebase Console to receive reports; forgetting this is a common cause of missing reports.

3. Step 3: Consider other options

   Calling crash before initialization or unsupported iOS versions are less common and usually cause app errors.

4. Final Answer:

   Forgetting to enable Crashlytics in Firebase Console -> Option B

5. Quick Check:

   Enable Crashlytics in Console to get reports [OK]

Hint: Always enable Crashlytics in Firebase Console after setup [OK]

Common Mistakes:

• Skipping Crashlytics enablement in Firebase Console
• Initializing Firebase incorrectly
• Assuming all iOS versions are supported

5. You want to test Crashlytics setup by forcing a crash in your Android app. Which code snippet correctly triggers a test crash that will appear in Firebase Console?

hard

A. FirebaseCrashlytics.getInstance().setCrashlyticsCollectionEnabled(false);

B. FirebaseCrashlytics.getInstance().log("Crash test");

C. throw new RuntimeException("Test Crash");

D. FirebaseCrashlytics.getInstance().recordException(new Exception("Test"));

Solution

1. Step 1: Identify code that forces a crash

   Throwing a RuntimeException immediately crashes the app, which Crashlytics detects and reports.

2. Step 2: Understand other options

   Logging or recording exceptions do not force a crash. Disabling collection prevents reporting.

3. Final Answer:

   throw new RuntimeException("Test Crash"); -> Option C

4. Quick Check:

   Throw exception to force crash for testing [OK]

Hint: Throw exception to force crash, not just log [OK]

Common Mistakes:

• Using log or recordException without crashing
• Disabling Crashlytics collection by mistake
• Expecting logs alone to trigger crash reports