diff --git a/AGENTS.md b/AGENTS.md
index 0a37d84c..b6152d5f 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -2,16 +2,18 @@
 
 ## Android Build — Google Play Services / FOSS Compatibility
 
-**Firebase is opt-in. Do NOT enable it accidentally.**
+**Firebase is on by default for Android and iOS builds.** Do not turn it off unless the build is an exceptional FOSS/F-Droid artifact.
 
-`android/google-services.json` is gitignored and may be present on disk for push notification development, but Firebase is only activated when you explicitly pass `-PfirebaseEnabled` to Gradle:
+`android/app/google-services.json` is required when Firebase is enabled. It does not decide the switch: a missing file fails the build, and a file on disk is ignored when Firebase is explicitly disabled.
 
-- **FOSS / APK / Aurora / Zapstore / F-Droid builds**: just `./gradlew assembleRelease` — Firebase stays off even if `google-services.json` is on disk.
-- **Firebase / FCM / Play Store builds**: `./gradlew bundleRelease -PfirebaseEnabled` — explicitly opt in.
+- **Default (local, test, production, Play Store)**: `./gradlew assembleRelease` or `./gradlew bundleRelease` — do not pass `-PfirebaseEnabled`.
+- **Opt out (F-Droid / FOSS)**: `./gradlew assembleRelease -PfirebaseEnabled=false`. npm scripts honor `FIREBASE_ENABLED=false`, which forwards that property.
 
-This guard is in `android/app/build.gradle`. Do NOT change this conditional to activate Firebase unconditionally based on file presence alone — that was the bug that broke FOSS distribution in June 2026.
+iOS builds bundle `ios/App/App/GoogleService-Info.plist` by default (`ios/App/scripts/bundle-firebase-config.sh`, run from `scripts/build-ios.sh` and as an Xcode build phase). Opt out with `FIREBASE_ENABLED=false`. A missing plist fails the build; the file's presence does not enable Firebase on its own.
 
-`google-services.json` is intentionally excluded from git (`android/.gitignore`). Never commit it.
+The guard is in `android/app/build.gradle`. Do NOT activate Firebase from file presence alone — that was the bug that broke FOSS distribution in June 2026.
+
+Never commit `google-services.json`.
 
 Full details, incident history, and F-Droid notes: `doc/android-firebase-gms.md`
 
diff --git a/BUILDING.md b/BUILDING.md
index a6f618b8..181572f4 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -1474,9 +1474,11 @@ So, to create a signed `aab` release:
 
 ```bash
 # if you use pkgx: pkgx +openjdk.org /bin/zsh
-./gradlew bundleRelease -Dlint.baselines.continue=true -PfirebaseEnabled
+./gradlew bundleRelease -Dlint.baselines.continue=true
 ```
 
+Firebase is on by default (`firebaseEnabled=true` in `android/gradle.properties`). Do not pass `-PfirebaseEnabled` for a normal release. F-Droid and other builds that must omit Firebase use `-PfirebaseEnabled=false`.
+
 ... and find your `aab` file at app/build/outputs/bundle/release
 
 * Gradle packages whatever web bundle was last synced into
@@ -1486,8 +1488,6 @@ So, to create a signed `aab` release:
 * `build-android.sh` runs `./gradlew clean`, which deletes any earlier `aab`, so
   run `bundleRelease` after the build script finishes.
 
-* Note that F-Droid builds should omit `-PfirebaseEnabled`.
-
 At play.google.com/console:
 
 - Go to Production or the Closed Testing and either Create Track or Manage Track.
diff --git a/android/app/build.gradle b/android/app/build.gradle
index 3fa73886..bf67d857 100644
--- a/android/app/build.gradle
+++ b/android/app/build.gradle
@@ -130,20 +130,32 @@ dependencies {
 
 apply from: 'capacitor.build.gradle'
 
-// Firebase / Google Play Services are opt-in. Pass -PfirebaseEnabled to any Gradle command
-// to activate Firebase (FCM push notifications). Without this flag the build works on
-// F-Droid, Aurora, Zapstore, and plain APK sideloading even when google-services.json
-// is present on disk (it is gitignored; see AGENTS.md for the full story).
-try {
-    def servicesJSON = file('google-services.json')
-    if (servicesJSON.exists() && servicesJSON.text && project.hasProperty('firebaseEnabled')) {
-        apply plugin: 'com.google.gms.google-services'
-        logger.info("Firebase enabled: google-services plugin applied")
-    } else if (servicesJSON.exists() && !project.hasProperty('firebaseEnabled')) {
-        logger.info("google-services.json present but firebaseEnabled not set — skipping Firebase plugin (pass -PfirebaseEnabled to enable)")
-    } else {
-        logger.info("google-services.json not found — Firebase plugin not applied")
+// Firebase is on for every build. Opt out only with -PfirebaseEnabled=false
+// (F-Droid / other builds that must not apply the google-services plugin).
+// The config file does not decide the switch: when Firebase is on, a missing
+// file fails the build; when it is off, a file on disk is ignored.
+def firebaseEnabledRaw = project.findProperty('firebaseEnabled')
+def firebaseEnabled = true
+if (firebaseEnabledRaw != null) {
+    def normalized = firebaseEnabledRaw.toString().trim().toLowerCase()
+    if (normalized == 'false' || normalized == '0' || normalized == 'no') {
+        firebaseEnabled = false
     }
-} catch(Exception e) {
-    logger.info("google-services plugin not applied: ${e.message}")
+}
+
+if (!firebaseEnabled) {
+    logger.lifecycle('Firebase disabled (-PfirebaseEnabled=false): google-services plugin not applied')
+} else {
+    def servicesJSON = file('google-services.json')
+    def servicesBody = servicesJSON.isFile() ? servicesJSON.getText('UTF-8') : ''
+    if (!servicesBody.trim() || !servicesBody.contains('mobilesdk_app_id')) {
+        throw new GradleException(
+            'Firebase is enabled, but android/app/google-services.json is missing, empty, or has no mobilesdk_app_id.\n' +
+            'Download it from the Firebase console (Project settings → Your apps → Android app)\n' +
+            'and place it at android/app/google-services.json.\n' +
+            'To build without Firebase (F-Droid / FOSS), pass -PfirebaseEnabled=false.'
+        )
+    }
+    apply plugin: 'com.google.gms.google-services'
+    logger.lifecycle('Firebase enabled: google-services plugin applied')
 }
diff --git a/android/app/src/main/java/app/timesafari/notifications/NotificationInspectorPlugin.java b/android/app/src/main/java/app/timesafari/notifications/NotificationInspectorPlugin.java
index 963322ec..b70c05b4 100644
--- a/android/app/src/main/java/app/timesafari/notifications/NotificationInspectorPlugin.java
+++ b/android/app/src/main/java/app/timesafari/notifications/NotificationInspectorPlugin.java
@@ -15,8 +15,8 @@ public class NotificationInspectorPlugin extends Plugin {
   }
 
   /**
-   * Whether this build carries a Firebase config, i.e. was built with
-   * -PfirebaseEnabled. Without it, PushNotifications.register() throws on the
+   * Whether this build carries a Firebase config. Normal builds do.
+   * -PfirebaseEnabled=false omits it. Without it, PushNotifications.register() throws on the
    * Capacitor plugin thread and kills the app, so JS must check this first.
    * The google-services Gradle plugin generates the google_app_id resource,
    * which is what Firebase's own auto-initialization looks for.
diff --git a/android/gradle.properties b/android/gradle.properties
index 98bddd32..bbda0b2e 100644
--- a/android/gradle.properties
+++ b/android/gradle.properties
@@ -22,3 +22,8 @@ org.gradle.jvmargs=-Xmx1536m --add-opens=jdk.compiler/com.sun.tools.javac.api=AL
 # https://developer.android.com/topic/libraries/support-library/androidx-rn
 android.useAndroidX=true
 android.suppressUnsupportedCompileSdk=36
+
+# Firebase/FCM is on for every Gradle build (Android Studio, ./gradlew, npm scripts).
+# Opt out with -PfirebaseEnabled=false. android/app/google-services.json does not
+# toggle this; a missing file fails the build while Firebase is enabled.
+firebaseEnabled=true
diff --git a/doc/android-firebase-gms.md b/doc/android-firebase-gms.md
index 2fde5452..b6de160d 100644
--- a/doc/android-firebase-gms.md
+++ b/doc/android-firebase-gms.md
@@ -2,49 +2,45 @@
 
 ## Overview
 
-The app is designed to work on Android devices with and without Google Play Services (GMS). Firebase/FCM push notifications are an opt-in feature at build time; all other functionality works on GMS-less devices (F-Droid, LineageOS without OpenGApps, etc.).
+The app is designed to work on Android devices with and without Google Play Services (GMS). Firebase/FCM is **on by default** for local, test, and production builds. GMS-less devices still run the app; FCM degrades when Play Services is absent. F-Droid and other builds that must omit Firebase opt out explicitly.
 
-## How the opt-in guard works
+## How the switch works
 
-`android/app/build.gradle` applies the `com.google.gms.google-services` Gradle plugin only when **both** conditions are true:
+`android/app/build.gradle` applies `com.google.gms.google-services` unless `firebaseEnabled` is `false`. `android/gradle.properties` sets `firebaseEnabled=true`, so Android Studio, `./gradlew`, and `scripts/build-android.sh` all pick it up. `-PfirebaseEnabled` and `-PfirebaseEnabled=true` stay on. The config file does not decide the switch.
 
-1. `android/google-services.json` is present on disk
-2. The Gradle property `firebaseEnabled` is explicitly passed
+When Firebase is on, `android/app/google-services.json` must exist, be non-empty, and contain `mobilesdk_app_id`. Otherwise configuration fails with an error that names that path. When Firebase is off, the file is ignored even if it is on disk.
 
-```groovy
-if (servicesJSON.exists() && servicesJSON.text && project.hasProperty('firebaseEnabled')) {
-    apply plugin: 'com.google.gms.google-services'
-}
-```
+`scripts/build-android.sh` forwards an opt-out: `FIREBASE_ENABLED=false` adds `-PfirebaseEnabled=false` to its Gradle commands. npm scripts do not pass `-PfirebaseEnabled`; they rely on the default.
 
-This means the file can live on disk for development purposes without accidentally activating Firebase.
+iOS uses the same default. `ios/App/scripts/bundle-firebase-config.sh` copies `ios/App/App/GoogleService-Info.plist` into the app and the share extension. `scripts/build-ios.sh` runs it with `--check` before a device build, and both Xcode targets run it as a build phase. `FIREBASE_ENABLED=false` skips the plist. A missing or empty plist fails the build when Firebase is on.
 
 ## Build commands
 
 | Target | Command | Firebase |
 |---|---|---|
-| APK / sideload / Zapstore | `./gradlew assembleRelease` | off |
-| Aurora / Play Store without FCM | `./gradlew bundleRelease` | off |
-| Play Store with FCM push notifications | `./gradlew bundleRelease -PfirebaseEnabled` | on |
-| F-Droid | `./gradlew assembleRelease` | off (required) |
+| Local / test / production APK or AAB | `./gradlew assembleRelease` or `bundleRelease` | on |
+| Play Store with FCM | `./gradlew bundleRelease` | on |
+| iOS (Xcode or `scripts/build-ios.sh`) | default | on |
+| F-Droid / FOSS Android | `./gradlew assembleRelease -PfirebaseEnabled=false` | off |
+| iOS without Firebase | `FIREBASE_ENABLED=false` | off |
 
 ## Behavior on non-GMS devices
 
-When built with `-PfirebaseEnabled`, Firebase SDKs check for GMS availability at startup and degrade gracefully if it is absent:
+When Firebase is enabled (the default), Firebase SDKs check for GMS availability at startup and degrade gracefully if it is absent:
 
 - Firebase initializes but detects no GMS
 - FCM skips token registration silently (no token, no notifications)
 - The app continues to work normally
 
-This means a single Play Store AAB (`bundleRelease -PfirebaseEnabled`) covers both GMS and non-GMS users. GMS users get push notifications; non-GMS users get a fully functional app without them.
+This means a single Play Store AAB (`bundleRelease`, Firebase on by default) covers both GMS and non-GMS users. GMS users get push notifications; non-GMS users get a fully functional app without them.
 
-**Aurora Store** pulls the exact APK from Play Store servers, so Aurora users get whichever variant was uploaded. The Play Store AAB built with `-PfirebaseEnabled` is correct for Aurora.
+**Aurora Store** pulls the exact APK from Play Store servers, so Aurora users get whichever variant was uploaded. The default Play Store AAB (Firebase on) is the one to upload.
 
-**F-Droid** is stricter: their build policy rejects any APK with GMS dependencies at the binary level, even with graceful degradation. F-Droid submission would require a separate `assembleRelease` build (no flag) and a dedicated F-Droid listing.
+**F-Droid** is stricter: their build policy rejects any APK with GMS dependencies at the binary level, even with graceful degradation. F-Droid submission would require a separate `assembleRelease -PfirebaseEnabled=false` build and a dedicated F-Droid listing.
 
 ## Push registration in builds without Firebase
 
-A build without `-PfirebaseEnabled` contains the `@capacitor/push-notifications` plugin, but no Firebase config. In that build, `PushNotifications.register()` throws `Default FirebaseApp is not initialized` on the Capacitor plugin thread, which kills the app; a JS `try/catch` cannot intercept it.
+A build with `-PfirebaseEnabled=false` contains the `@capacitor/push-notifications` plugin, but no Firebase config. In that build, `PushNotifications.register()` throws `Default FirebaseApp is not initialized` on the Capacitor plugin thread, which kills the app; a JS `try/catch` cannot intercept it.
 
 The JS therefore asks native code first. `NotificationInspector.isFirebaseConfigured()` (`android/app/src/main/java/app/timesafari/notifications/NotificationInspectorPlugin.java`) reports whether the `google_app_id` string resource exists; the google-services Gradle plugin generates that resource only when Firebase is enabled, and it is the same signal Firebase's auto-initialization uses. `firebaseMessagingClient.ts` skips `register()` on Android when it is absent (or when the check fails), logging `No Firebase config in this Android build; skipping push registration`. Listener setup and the notification permission request run either way, since local daily notifications need that permission.
 
@@ -56,7 +52,8 @@ Any code that calls `PushNotifications.register()` or other `FirebaseMessaging`
 
 - Gitignored (`android/.gitignore` line 80) — never commit it
 - Contains Firebase project credentials (project number, app ID, API key)
-- Safe to leave on disk; has no effect unless `-PfirebaseEnabled` is passed
+- Required for the default (Firebase on) build. Place it at `android/app/google-services.json`
+- Ignored when you pass `-PfirebaseEnabled=false`; leaving it on disk does not re-enable Firebase
 - Obtain from the Firebase console: Project Settings → Your apps → Android app → Download `google-services.json`
 
 ## Known GMS dependency: MLKit barcode scanner
diff --git a/doc/local-android-testing-ngrok.md b/doc/local-android-testing-ngrok.md
index f3e032c9..294bb560 100644
--- a/doc/local-android-testing-ngrok.md
+++ b/doc/local-android-testing-ngrok.md
@@ -240,7 +240,7 @@ Complete this section once before your first physical-device push test. If Fireb
 
 2. The repo gitignores this file — each developer keeps a local copy; never commit it.
 
-3. Rebuild so Gradle applies the Google Services plugin (`android/app/build.gradle` applies `com.google.gms.google-services` when the file exists). If the file is missing, the build logs: *google-services.json not found, google-services plugin not applied. Push Notifications won't work*.
+3. Rebuild. Firebase is on by default, so Gradle applies the Google Services plugin. If `android/app/google-services.json` is missing or empty, the build stops and names that path. Opt out only with `-PfirebaseEnabled=false` or `FIREBASE_ENABLED=false`.
 
 4. Sync Capacitor if you changed native config:
 
@@ -928,11 +928,11 @@ Compare with panel **Backend Status** and Event Log error text.
 
 ### Gradle: Push Notifications won't work
 
-**Symptoms:** Build log: `google-services.json not found, google-services plugin not applied`.
+**Symptoms:** Build fails: `android/app/google-services.json is missing, empty, or has no mobilesdk_app_id`.
 
 **Likely causes:** Missing `android/app/google-services.json`.
 
-**Verification:** File exists on disk; rebuild shows Google Services plugin applied.
+**Verification:** File exists on disk and the build log says `Firebase enabled: google-services plugin applied`.
 
 **Fixes:** Download from Firebase Console (package `app.timesafari.app`); place in `android/app/`; `npx cap sync android` and rebuild.
 
diff --git a/ios/App/App.xcodeproj/project.pbxproj b/ios/App/App.xcodeproj/project.pbxproj
index cccb52cf..5c74a99c 100644
--- a/ios/App/App.xcodeproj/project.pbxproj
+++ b/ios/App/App.xcodeproj/project.pbxproj
@@ -19,8 +19,6 @@
 		C86585DF2ED456DE00824752 /* TimeSafariShareExtension.appex in Embed Foundation Extensions */ = {isa = PBXBuildFile; fileRef = C86585D52ED456DE00824752 /* TimeSafariShareExtension.appex */; settings = {ATTRIBUTES = (RemoveHeadersOnCopy, ); }; };
 		C8C56E142EE0474B00737D0E /* SharedImageUtility.swift in Sources */ = {isa = PBXBuildFile; fileRef = C8C56E132EE0474B00737D0E /* SharedImageUtility.swift */; };
 		C8C56E162EE064CB00737D0E /* SharedImagePlugin.swift in Sources */ = {isa = PBXBuildFile; fileRef = C8C56E152EE064CA00737D0E /* SharedImagePlugin.swift */; };
-		C8E73DD12FC6E5DC0057F59A /* GoogleService-Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = C8E73DD02FC6E5DC0057F59A /* GoogleService-Info.plist */; };
-		C8E73DD22FC6E5DC0057F59A /* GoogleService-Info.plist in Resources */ = {isa = PBXBuildFile; fileRef = C8E73DD02FC6E5DC0057F59A /* GoogleService-Info.plist */; };
 		E9F1A0022EE05A8B00737D01 /* NotificationInspectorPlugin.swift in Sources */ = {isa = PBXBuildFile; fileRef = E9F1A0012EE05A8B00737D01 /* NotificationInspectorPlugin.swift */; };
 /* End PBXBuildFile section */
 
@@ -185,6 +183,7 @@
 				504EC3001FED79650016851F /* Sources */,
 				504EC3011FED79650016851F /* Frameworks */,
 				504EC3021FED79650016851F /* Resources */,
+				F1REBA5E000000000000A001 /* Bundle Firebase Config */,
 				012076E8FFE4BF260A79B034 /* Fix Privacy Manifest */,
 				96A7EF592DF3366D00084D51 /* Fix Privacy Manifest */,
 				C86585E02ED456DE00824752 /* Embed Foundation Extensions */,
@@ -207,6 +206,7 @@
 				C86585D12ED456DE00824752 /* Sources */,
 				C86585D22ED456DE00824752 /* Frameworks */,
 				C86585D32ED456DE00824752 /* Resources */,
+				F1REBA5E000000000000A002 /* Bundle Firebase Config */,
 			);
 			buildRules = (
 			);
@@ -270,7 +270,6 @@
 				50379B232058CBB4000EE86E /* capacitor.config.json in Resources */,
 				504EC30D1FED79650016851F /* Main.storyboard in Resources */,
 				2FAD9763203C412B000D30F8 /* config.xml in Resources */,
-				C8E73DD12FC6E5DC0057F59A /* GoogleService-Info.plist in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -278,7 +277,6 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
-				C8E73DD22FC6E5DC0057F59A /* GoogleService-Info.plist in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -342,6 +340,48 @@
 			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
 			showEnvVarsInLog = 0;
 		};
+		F1REBA5E000000000000A001 /* Bundle Firebase Config */ = {
+			isa = PBXShellScriptBuildPhase;
+			alwaysOutOfDate = 1;
+			buildActionMask = 2147483647;
+			enableUserScriptSandboxing = 0;
+			files = (
+			);
+			inputFileListPaths = (
+			);
+			inputPaths = (
+			);
+			name = "Bundle Firebase Config";
+			outputFileListPaths = (
+			);
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "\"${PROJECT_DIR}/scripts/bundle-firebase-config.sh\"\n";
+			showEnvVarsInLog = 0;
+		};
+		F1REBA5E000000000000A002 /* Bundle Firebase Config */ = {
+			isa = PBXShellScriptBuildPhase;
+			alwaysOutOfDate = 1;
+			buildActionMask = 2147483647;
+			enableUserScriptSandboxing = 0;
+			files = (
+			);
+			inputFileListPaths = (
+			);
+			inputPaths = (
+			);
+			name = "Bundle Firebase Config";
+			outputFileListPaths = (
+			);
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "\"${PROJECT_DIR}/scripts/bundle-firebase-config.sh\"\n";
+			showEnvVarsInLog = 0;
+		};
 		96A7EF592DF3366D00084D51 /* Fix Privacy Manifest */ = {
 			isa = PBXShellScriptBuildPhase;
 			alwaysOutOfDate = 1;
diff --git a/ios/App/scripts/bundle-firebase-config.sh b/ios/App/scripts/bundle-firebase-config.sh
new file mode 100755
index 00000000..078d8d5c
--- /dev/null
+++ b/ios/App/scripts/bundle-firebase-config.sh
@@ -0,0 +1,61 @@
+#!/bin/sh
+# Bundle GoogleService-Info.plist when Firebase is enabled (the default).
+# Opt out with FIREBASE_ENABLED=false. The plist does not decide the switch:
+# a missing file fails an enabled build, and an opt-out build does not bundle
+# the plist even when the file is on disk.
+#
+# Xcode run-script phases invoke this with no arguments. build-ios.sh may pass
+# --check to validate before a long build without copying into a product.
+set -eu
+
+check_only=0
+if [ "${1:-}" = "--check" ]; then
+  check_only=1
+fi
+
+if [ -z "${SRCROOT:-}" ]; then
+  script_dir=$(CDPATH= cd -- "$(dirname "$0")" && pwd)
+  SRCROOT=$(CDPATH= cd -- "$script_dir/.." && pwd)
+fi
+
+normalized=$(printf '%s' "${FIREBASE_ENABLED:-true}" | tr '[:upper:]' '[:lower:]')
+plist="${SRCROOT}/App/GoogleService-Info.plist"
+
+firebase_off=0
+case "$normalized" in
+  false|0|no) firebase_off=1 ;;
+esac
+
+if [ "$firebase_off" -eq 1 ]; then
+  if [ "$check_only" -eq 0 ]; then
+    dest_dir="${TARGET_BUILD_DIR:-}/${UNLOCALIZED_RESOURCES_FOLDER_PATH:-}"
+    if [ -n "${TARGET_BUILD_DIR:-}" ] && [ -n "${UNLOCALIZED_RESOURCES_FOLDER_PATH:-}" ]; then
+      rm -f "${dest_dir}/GoogleService-Info.plist"
+    fi
+  fi
+  echo "note: Firebase disabled (FIREBASE_ENABLED=false); GoogleService-Info.plist will not be bundled."
+  exit 0
+fi
+
+if [ ! -s "$plist" ] || ! grep -q "GOOGLE_APP_ID" "$plist"; then
+  echo "error: Firebase is enabled, but ios/App/App/GoogleService-Info.plist is missing, empty, or has no GOOGLE_APP_ID." >&2
+  echo "error: Download it from the Firebase console (Project settings → Your apps → Apple apps)" >&2
+  echo "error: and place it at ios/App/App/GoogleService-Info.plist." >&2
+  echo "error: To build without Firebase, set FIREBASE_ENABLED=false." >&2
+  exit 1
+fi
+
+if [ "$check_only" -eq 1 ]; then
+  echo "note: Firebase enabled; ios/App/App/GoogleService-Info.plist is present."
+  exit 0
+fi
+
+if [ -z "${TARGET_BUILD_DIR:-}" ] || [ -z "${UNLOCALIZED_RESOURCES_FOLDER_PATH:-}" ]; then
+  echo "error: Bundle Firebase Config must run as an Xcode build phase (TARGET_BUILD_DIR is unset)." >&2
+  exit 1
+fi
+
+dest_dir="${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}"
+mkdir -p "$dest_dir"
+cp "$plist" "${dest_dir}/GoogleService-Info.plist"
+echo "note: Firebase enabled; bundled GoogleService-Info.plist."
diff --git a/scripts/build-android.sh b/scripts/build-android.sh
index 129e94c8..c953ab4c 100755
--- a/scripts/build-android.sh
+++ b/scripts/build-android.sh
@@ -23,6 +23,7 @@
 #   --assets                Generate assets only
 #   --deploy                Deploy APK to connected device
 #   --uninstall             Uninstall app from connected device
+#   FIREBASE_ENABLED=false  Opt out of Firebase (-PfirebaseEnabled=false)
 #   -h, --help             Show this help message
 #   -v, --verbose          Enable verbose logging
 #
@@ -439,6 +440,9 @@ print_android_usage() {
     echo "  --uninstall             Uninstall app from connected device"
     echo "  --api-ip <ip>          Custom IP address for claim API (defaults to 10.0.2.2)"
     echo ""
+    echo "Firebase is on by default. Opt out with FIREBASE_ENABLED=false"
+    echo "(passes -PfirebaseEnabled=false to Gradle)."
+    echo ""
     echo "Common Options:"
     echo "  -h, --help             Show this help message"
     echo "  -v, --verbose          Enable verbose logging"
@@ -460,6 +464,17 @@ print_android_usage() {
 # Parse command line arguments
 parse_android_args "$@"
 
+# Firebase is on unless FIREBASE_ENABLED is false, 0, or no. Gradle also
+# defaults firebaseEnabled=true; this only forwards an explicit opt-out.
+gradle_firebase_arg=""
+firebase_enabled_normalized=$(printf '%s' "${FIREBASE_ENABLED:-true}" | tr '[:upper:]' '[:lower:]')
+case "$firebase_enabled_normalized" in
+    false|0|no)
+        gradle_firebase_arg="-PfirebaseEnabled=false"
+        log_info "Firebase disabled for this Android build (FIREBASE_ENABLED=${FIREBASE_ENABLED})"
+        ;;
+esac
+
 # Print build header
 print_header "TimeSafari Android Build Process"
 
@@ -528,7 +543,7 @@ if [ "$CLEAN_ONLY" = true ]; then
     log_info "Clean-only mode: cleaning build artifacts"
     safe_execute "Cleaning Android app" "npm run clean:android" || exit 1
     safe_execute "Cleaning dist directory" "clean_build_artifacts dist" || exit 1
-    safe_execute "Cleaning Gradle build" "cd android && ./gradlew clean && cd .." || exit 4
+    safe_execute "Cleaning Gradle build" "cd android && ./gradlew clean ${gradle_firebase_arg} && cd .." || exit 4
     log_success "Clean completed successfully!"
     exit 0
 fi
@@ -561,7 +576,7 @@ if [ "$DEPLOY_APP" = true ]; then
     fi
     
     # Build APK
-    safe_execute "Building APK" "cd android && ./gradlew assembleDebug && cd .." || exit 5
+    safe_execute "Building APK" "cd android && ./gradlew assembleDebug ${gradle_firebase_arg} && cd .." || exit 5
     
     # Install APK on device
     safe_execute "Installing APK on device" "adb install -r android/app/build/outputs/apk/debug/app-debug.apk" || exit 6
@@ -628,26 +643,26 @@ fi
 safe_execute "Generating assets" "npx capacitor-assets generate --android --assetPath resources" || exit 7
 
 # Step 8: Clean Gradle build
-safe_execute "Cleaning Gradle build" "cd android && ./gradlew clean && cd .." || exit 4
+safe_execute "Cleaning Gradle build" "cd android && ./gradlew clean ${gradle_firebase_arg} && cd .." || exit 4
 
 # Step 9: Build based on type
 if [ "$BUILD_TYPE" = "debug" ]; then
-    safe_execute "Assembling debug build" "cd android && ./gradlew assembleDebug && cd .." || exit 5
+    safe_execute "Assembling debug build" "cd android && ./gradlew assembleDebug ${gradle_firebase_arg} && cd .." || exit 5
 elif [ "$BUILD_TYPE" = "release" ]; then
-    safe_execute "Assembling release build" "cd android && ./gradlew assembleRelease && cd .." || exit 5
+    safe_execute "Assembling release build" "cd android && ./gradlew assembleRelease ${gradle_firebase_arg} && cd .." || exit 5
 fi
 
 # Step 10: Build APK/AAB if requested
 if [ "$BUILD_APK" = true ]; then
     if [ "$BUILD_TYPE" = "debug" ]; then
-        safe_execute "Building debug APK" "cd android && ./gradlew assembleDebug && cd .." || exit 5
+        safe_execute "Building debug APK" "cd android && ./gradlew assembleDebug ${gradle_firebase_arg} && cd .." || exit 5
     else
-        safe_execute "Building release APK" "cd android && ./gradlew assembleRelease && cd .." || exit 5
+        safe_execute "Building release APK" "cd android && ./gradlew assembleRelease ${gradle_firebase_arg} && cd .." || exit 5
     fi
 fi
 
 if [ "$BUILD_AAB" = true ]; then
-    safe_execute "Building AAB" "cd android && ./gradlew bundleRelease && cd .." || exit 5
+    safe_execute "Building AAB" "cd android && ./gradlew bundleRelease ${gradle_firebase_arg} && cd .." || exit 5
     if [ "$BUILD_MODE" = "production" ]; then
         safe_execute "Checking production AAB" "./scripts/check-prod-bundle.sh android/app/build/outputs/bundle/release/app-release.aab" || exit 10
     fi
diff --git a/scripts/build-ios.sh b/scripts/build-ios.sh
index b432c124..100efb81 100755
--- a/scripts/build-ios.sh
+++ b/scripts/build-ios.sh
@@ -44,6 +44,8 @@ print_ios_usage() {
     echo "  --auto-run              Auto-run app after build"
     echo "  --api-ip <ip>          Custom IP address for claim API (uses Capacitor default)"
     echo ""
+    echo "Firebase is on by default. Opt out with FIREBASE_ENABLED=false."
+    echo ""
     echo "Common Options:"
     echo "  -h, --help             Show this help message"
     echo "  -v, --verbose          Enable verbose logging"
@@ -537,6 +539,13 @@ if [ "$ASSETS_ONLY" = true ]; then
     exit 0
 fi
 
+# Firebase is on unless FIREBASE_ENABLED=false. Fail before the web build and
+# xcodebuild when the plist is missing. Xcode runs the same script as a build
+# phase so GUI builds get the same check and bundle the plist.
+if ! ios/App/scripts/bundle-firebase-config.sh --check; then
+    exit 1
+fi
+
 # Handle deploy-app mode
 if [ "$DEPLOY_APP" = true ]; then
     deploy_ios_app
diff --git a/src/plugins/NotificationInspectorPlugin.ts b/src/plugins/NotificationInspectorPlugin.ts
index 27d6885b..bd426f75 100644
--- a/src/plugins/NotificationInspectorPlugin.ts
+++ b/src/plugins/NotificationInspectorPlugin.ts
@@ -11,7 +11,7 @@ export type PendingNotificationInfo = {
 
 export interface NotificationInspectorPlugin {
   getPendingNotifications(): Promise<{ pending: PendingNotificationInfo[] }>;
-  /** Android only: whether the build has a Firebase config (-PfirebaseEnabled). */
+  /** Android only: whether this build included Firebase (off only with -PfirebaseEnabled=false). */
   isFirebaseConfigured(): Promise<{ configured: boolean }>;
 }
 
diff --git a/src/services/notifications/firebaseMessagingClient.ts b/src/services/notifications/firebaseMessagingClient.ts
index 5558c08e..cc7f475c 100644
--- a/src/services/notifications/firebaseMessagingClient.ts
+++ b/src/services/notifications/firebaseMessagingClient.ts
@@ -69,9 +69,10 @@ async function registerRetrievedToken(
 }
 
 /**
- * Whether PushNotifications.register() is safe to call. Android builds without
- * -PfirebaseEnabled (FOSS/F-Droid/APK) have no Firebase config, and register()
- * there throws natively, crashing the app before any JS catch can run.
+ * Whether PushNotifications.register() is safe to call. Android builds with
+ * Firebase disabled (-PfirebaseEnabled=false, FOSS/F-Droid) have no Firebase
+ * config, and register() there throws natively, crashing the app before any
+ * JS catch can run.
  */
 async function canRegisterNativePush(): Promise<boolean> {
   if (Capacitor.getPlatform() !== "android") {
@@ -101,7 +102,7 @@ export async function reregisterFcmTokenNow(): Promise<string> {
 
   if (!(await canRegisterNativePush())) {
     throw new Error(
-      "Push is unavailable: this Android build has no Firebase config (built without -PfirebaseEnabled)",
+      "Push is unavailable: this Android build has no Firebase config (built with -PfirebaseEnabled=false)",
     );
   }