ITMS-90683: Missing purpose string in Info.plist.

What you see

You upload a build and Apple emails you ITMS-90683. It says a purpose string is missing. Often it is NSLocationAlwaysAndWhenInUseUsageDescription, even though your app only uses location while it is open.

Or the problem shows up on a device. The app crashes the first time it asks for location. Or a camera plugin errors out and App Review rejects the build under Guideline 2.1(a).

Why it happens

iOS needs a usage description string, the NS...UsageDescription keys, for every protected feature an app can request. Two things trip people up.

Plugins reference APIs you never call. Capacitor geolocation plugins reference the Always location API inside their binary. Apple scans the binary, sees the reference, and wants the matching purpose string, even if your code only asks for While Using.

A missing string is a crash, not a warning. If the app requests a permission without its string, iOS kills the app. A missing NSLocationWhenInUseUsageDescription crashes the location prompt. Some plugins also need strings you think are unused. Removing an "orphaned" NSPhotoLibraryAddUsageDescription once broke a camera plugin.

The opposite problem exists too. Purpose strings for features you do not use, like the microphone or photo saving, draw review questions and can contradict your privacy policy.

The fix, step by step

Step 1. List your plugins. Open package.json and write down every native plugin. For each one, read its install docs and note the Info.plist keys it requires.

Step 2. Add both location keys if you use any location plugin. Use honest wording that says what the app does with location:

<key>NSLocationWhenInUseUsageDescription</key>
<string>Your location is used to show nearby jobs while the app is open.</string>
<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
<string>Your location is used to show nearby jobs while the app is open.</string>

Step 3. Add every string your camera and photo plugins can trigger. For a typical camera plugin that means:

NSCameraUsageDescription
NSPhotoLibraryUsageDescription
NSPhotoLibraryAddUsageDescription

Step 4. Remove only what nothing uses. Go through the rest of your keys. For each one, point to the line of code or the plugin that reads it. If you cannot, and no plugin docs mention it, remove it. Template and copied config often leave NSMicrophoneUsageDescription behind. Do the same on Android and remove unused permissions such as RECORD_AUDIO from AndroidManifest.xml.

In Expo, these keys live in app.json under ios.infoPlist, and Android permissions under android.permissions. Edit them there, then rebuild.

Step 5. Add a CI check. Make the build fail when a required key is missing, so this never reaches Apple again:

PLIST=ios/App/App/Info.plist
for key in NSLocationWhenInUseUsageDescription \
           NSLocationAlwaysAndWhenInUseUsageDescription \
           NSCameraUsageDescription; do
  grep -q "<key>$key</key>" "$PLIST" || { echo "Missing $key"; exit 1; }
done

Adjust the list to match your plugins. Then rebuild and upload.

Step 6. Test the prompts on a real device. Trigger every permission the app can ask for. If any prompt crashes the app, a string is still missing.

How to prevent it

• Audit Info.plist against the plugins in package.json before every submission.
• Never delete a usage string without checking which plugin reads it.
• Keep the key check in CI so a missing string fails your build, not your review.

Related traps

• Background location fails silently. iOS often grants only While Using, and the error lands in console.log where nobody on a phone can see it. Show permission state in the UI.
• Android background location. It needs ACCESS_BACKGROUND_LOCATION, which the plugin does not merge in, plus an in-app disclosure that Play requires.
• Missing Compliance. Add ITSAppUsesNonExemptEncryption while you are in Info.plist, or your next TestFlight build may reach nobody.

Keep reading.