diff --git a/package.json b/package.json
index e4fbefe..fbe3f20 100644
--- a/package.json
+++ b/package.json
@@ -54,6 +54,7 @@
     "zip-webpack-plugin": "^3.0.0"
   },
   "dependencies": {
-    "terser-webpack-plugin": "^2.2.1"
+    "terser-webpack-plugin": "^2.2.1",
+    "webextension-polyfill": "^0.5.0"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index 0386606..b7de04d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7155,6 +7155,11 @@ wbuf@^1.1.0, wbuf@^1.7.3:
   dependencies:
     minimalistic-assert "^1.0.0"
 
+webextension-polyfill@^0.5.0:
+  version "0.5.0"
+  resolved "https://registry.yarnpkg.com/webextension-polyfill/-/webextension-polyfill-0.5.0.tgz#795e0bf6a2b8eadcdb6edaecd169e9228c747519"
+  integrity sha512-aFrl38x43t1bTboX/paCT8I97+idzX/TY0+fuM52hrIkCpYfROEF9kSn0BXuEIi3J9LTYt2ZZKkhx9NB1qF3nA==
+
 webpack-cli@^3.3.9:
   version "3.3.9"
   resolved "https://registry.yarnpkg.com/webpack-cli/-/webpack-cli-3.3.9.tgz#79c27e71f94b7fe324d594ab64a8e396b9daa91a"