diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4720f5e..238f426 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -30,7 +30,11 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-gradle-
       - run: flutter pub get
-      - run: flutter build apk --release --no-pub
+      - name: Write dart_defines.json
+        env:
+          GIPHY_API_KEY: ${{ secrets.GIPHY_API_KEY }}
+        run: jq -n --arg k "$GIPHY_API_KEY" '{GIPHY_API_KEY:$k}' > dart_defines.json
+      - run: flutter build apk --release --no-pub --dart-define-from-file=dart_defines.json
       - name: Upload APK
         uses: actions/upload-artifact@v4
         with:
@@ -61,7 +65,11 @@ jobs:
       - name: Install Linux build deps
         run: sudo apt-get update && sudo apt-get install -y clang cmake ninja-build pkg-config libgtk-3-dev
       - run: flutter pub get
-      - run: flutter build linux --release --no-pub
+      - name: Write dart_defines.json
+        env:
+          GIPHY_API_KEY: ${{ secrets.GIPHY_API_KEY }}
+        run: jq -n --arg k "$GIPHY_API_KEY" '{GIPHY_API_KEY:$k}' > dart_defines.json
+      - run: flutter build linux --release --no-pub --dart-define-from-file=dart_defines.json
       - name: Upload Linux bundle
         uses: actions/upload-artifact@v4
         with:
@@ -90,7 +98,11 @@ jobs:
           flutter-version: "3.44.1"
           cache: true
       - run: flutter pub get
-      - run: flutter build web --release --no-pub
+      - name: Write dart_defines.json
+        env:
+          GIPHY_API_KEY: ${{ secrets.GIPHY_API_KEY }}
+        run: jq -n --arg k "$GIPHY_API_KEY" '{GIPHY_API_KEY:$k}' > dart_defines.json
+      - run: flutter build web --release --no-pub --dart-define-from-file=dart_defines.json
       - name: Upload web build
         uses: actions/upload-artifact@v4
         with:
@@ -108,7 +120,15 @@ jobs:
           flutter-version: "3.44.1"
           cache: true
       - run: flutter pub get
-      - run: flutter build windows --release --no-pub
+      # Windows runner defaults to PowerShell; jq is not guaranteed there,
+      # so build the JSON with ConvertTo-Json, which escapes correctly.
+      - name: Write dart_defines.json
+        env:
+          GIPHY_API_KEY: ${{ secrets.GIPHY_API_KEY }}
+        run: |
+          @{ GIPHY_API_KEY = $env:GIPHY_API_KEY } | ConvertTo-Json -Compress |
+            Set-Content -Path dart_defines.json -Encoding utf8 -NoNewline
+      - run: flutter build windows --release --no-pub --dart-define-from-file=dart_defines.json
       - name: Upload Windows build
         uses: actions/upload-artifact@v4
         with: