diff --git a/extension/injected.js b/extension/injected.js
new file mode 100644
index 0000000..61e4d73
--- /dev/null
+++ b/extension/injected.js
@@ -0,0 +1,29 @@
+(() => {
+  if (window.inscriboor) return;
+  const pending = new Map();
+  window.addEventListener("message", event => {
+    if (event.source !== window || event.data?.source !== "inscriboor-extension") return;
+    const request = pending.get(event.data.id);
+    if (!request) return;
+    pending.delete(event.data.id);
+    event.data.error ? request.reject(new Error(event.data.error)) : request.resolve(event.data.result);
+  });
+  const provider = Object.freeze({
+    isInscriboor: true,
+    request({ method, params = {} } = {}) {
+      if (typeof method !== "string" || !method) return Promise.reject(new Error("A provider method is required."));
+      const id = crypto.randomUUID();
+      return new Promise((resolve, reject) => {
+        pending.set(id, { resolve, reject });
+        window.postMessage({ source: "inscriboor-page", id, method, params }, "*");
+        setTimeout(() => {
+          if (!pending.has(id)) return;
+          pending.delete(id);
+          reject(new Error("Inscriboor request timed out."));
+        }, 120000);
+      });
+    }
+  });
+  Object.defineProperty(window, "inscriboor", { value: provider, configurable: false, writable: false });
+  window.dispatchEvent(new Event("inscriboor#initialized"));
+})();