diff --git a/extension/content.js b/extension/content.js
new file mode 100644
index 0000000..6da0e9c
--- /dev/null
+++ b/extension/content.js
@@ -0,0 +1,20 @@
+(() => {
+  const script = document.createElement("script");
+  script.src = chrome.runtime.getURL("injected.js");
+  script.onload = () => script.remove();
+  (document.documentElement || document.head).appendChild(script);
+
+  let port;
+  const connect = () => {
+    port = chrome.runtime.connect({ name: "inscriboor-provider" });
+    port.onMessage.addListener(message => window.postMessage({ source: "inscriboor-extension", ...message }, "*"));
+    port.onDisconnect.addListener(() => { port = null; });
+  };
+  connect();
+
+  window.addEventListener("message", event => {
+    if (event.source !== window || event.data?.source !== "inscriboor-page") return;
+    if (!port) connect();
+    port.postMessage({ id:event.data.id, method:event.data.method, params:event.data.params, origin:location.origin });
+  });
+})();