diff --git a/src/WebhookAPI/index.ts b/src/WebhookAPI/index.ts
index bbe0103..c02b546 100644
--- a/src/WebhookAPI/index.ts
+++ b/src/WebhookAPI/index.ts
@@ -7,5 +7,61 @@
  * @see    https://greatdetail.com
  */
 import AbstractAPI from "../API/AbstractAPI";
+import WebhookAPIError from "./WebhookAPIError";
+import { IncomingMessage, ServerResponse } from "http";
 
-export default class WebhookAPI extends AbstractAPI {}
+/**
+ * Webhook API.
+ *
+ * @since 1.0.0
+ * @author Dom Webber <dom.webber@hotmail.com>
+ * @example
+ * // Receive Registration Requests via Webhook
+ * const app = express(); // or any other express-like app
+ * app.get(
+ *   "/path/to/webhook",
+ *   async (req, res) => {
+ *     const reg = await sdk.webhook.register(req, res);
+ *     // DIY: Check the reg.verifyToken value
+ *     return reg.accept();
+ *   }
+ * )
+ * @example
+ * // Receive a Message via Webhook
+ * const app = express(); // or any other express-like app
+ * app.post("/path/to/webhook", sdk.webhook.eventNotification);
+ * app.listen(3000);
+ */
+export default class WebhookAPI extends AbstractAPI {
+  public async register(req: IncomingMessage, res: ServerResponse) {
+    const urlString = req.url;
+    if (!urlString) {
+      throw new WebhookAPIError("No URL in request");
+    }
+
+    const url = new URL(urlString);
+    const hubMode = url.searchParams.get("hub.mode");
+    const hubChallenge = url.searchParams.get("hub.challenge");
+    const hubVerifyToken = url.searchParams.get("hub.verify_token");
+
+    if (!hubMode || hubMode !== "subscribe") {
+      throw new WebhookAPIError("Invalid or unsupported hub.mode in request");
+    }
+
+    if (!hubChallenge) {
+      throw new WebhookAPIError("Invalid hub.challenge in request");
+    }
+
+    if (!hubVerifyToken) {
+      throw new WebhookAPIError("Invalid hub.verify_token in request");
+    }
+
+    return {
+      verifyToken: hubVerifyToken,
+      challenge: hubChallenge,
+      accept: () => {
+        return res.end(hubChallenge);
+      },
+    };
+  }
+}