diff --git a/bitrise.yml b/bitrise.yml
index 7481006..cb11e31 100644
--- a/bitrise.yml
+++ b/bitrise.yml
@@ -43,9 +43,18 @@ workflows:
           inputs:
             - content: |
                 echo "DEVELOPMENT_TEAM = $DEVELOPMENT_TEAM" >> "$BITRISE_SOURCE_DIR/Darwin/fastlane/AppStore.xcconfig"
-                cat > "$BITRISE_SOURCE_DIR/Darwin/fastlane/apikey.json" <<EOF
-                {"key_id":"$ASC_KEY_ID","issuer_id":"$ASC_ISSUER_ID","key":"$ASC_KEY_CONTENT","in_house":false}
-                EOF
+                # ASC_KEY_CONTENT is the raw multi-line .p8 PEM content — build
+                # the JSON with Ruby's encoder so its embedded newlines get
+                # escaped correctly instead of breaking the JSON string.
+                export APIKEY_PATH="$BITRISE_SOURCE_DIR/Darwin/fastlane/apikey.json"
+                ruby -rjson -e '
+                  File.write(ENV["APIKEY_PATH"], JSON.generate({
+                    "key_id" => ENV["ASC_KEY_ID"],
+                    "issuer_id" => ENV["ASC_ISSUER_ID"],
+                    "key" => ENV["ASC_KEY_CONTENT"],
+                    "in_house" => false
+                  }))
+                '
       - fastlane@3:
           inputs:
             - lane: beta
@@ -77,9 +86,18 @@ workflows:
           inputs:
             - content: |
                 echo "DEVELOPMENT_TEAM = $DEVELOPMENT_TEAM" >> "$BITRISE_SOURCE_DIR/Darwin/fastlane/AppStore.xcconfig"
-                cat > "$BITRISE_SOURCE_DIR/Darwin/fastlane/apikey.json" <<EOF
-                {"key_id":"$ASC_KEY_ID","issuer_id":"$ASC_ISSUER_ID","key":"$ASC_KEY_CONTENT","in_house":false}
-                EOF
+                # ASC_KEY_CONTENT is the raw multi-line .p8 PEM content — build
+                # the JSON with Ruby's encoder so its embedded newlines get
+                # escaped correctly instead of breaking the JSON string.
+                export APIKEY_PATH="$BITRISE_SOURCE_DIR/Darwin/fastlane/apikey.json"
+                ruby -rjson -e '
+                  File.write(ENV["APIKEY_PATH"], JSON.generate({
+                    "key_id" => ENV["ASC_KEY_ID"],
+                    "issuer_id" => ENV["ASC_ISSUER_ID"],
+                    "key" => ENV["ASC_KEY_CONTENT"],
+                    "in_house" => false
+                  }))
+                '
       - fastlane@3:
           inputs:
             - lane: release