How to Check iOS Device Logs for Debugging Crashes

"It crashes on startup."

This is the most useless feedback a beta tester can give. To fix the bug, you need the stack trace. But how do you get logs from an iPhone that isn't connected to your debugger?

Method 1: Console.app (macOS)

This is the standard way to view real-time logs from any iOS device.

1. Connect your iPhone to your Mac via USB.
2. Open the Console app (press Cmd+Space and type "Console").
3. In the sidebar, select your iPhone under "Devices".
4. Click Start (or verify it's already streaming).

You will see thousands of messages flying by. To find your app:
- Type your app's name in the Search bar.
- Or filter by "Process" to only show your executable.

Method 2: Sysdiagnose (No Computer)

If a tester is out in the wild, they can trigger a sysdiagnose.

1. Press and hold both Volume buttons + Power button for 1-1.5 seconds. You should feel a short vibration.
2. Wait about 10 minutes (it takes time to gather logs).
3. Go to Settings > Privacy > Analytics & Improvements > Analytics Data.
4. Scroll down to find the sysdiagnose_... file.
5. Tap share and Airdrop/Email it to the developer.

Note: This is heavy and contains logs for the entire system.

Method 3: In-App Logging Tools

Smart developers embed logging tools into the beta build. Services like Bugsnag, Sentry, or Firebase Crashlytics automatically upload crash reports the next time the app launches. This is far more reliable than asking users to capture logs manually.