diff --git a/packages/backend/src/controllers/paddle/webhooks.ee.ts b/packages/backend/src/controllers/paddle/webhooks.ee.ts
index 272bbfdb..41ed90da 100644
--- a/packages/backend/src/controllers/paddle/webhooks.ee.ts
+++ b/packages/backend/src/controllers/paddle/webhooks.ee.ts
@@ -1,11 +1,12 @@
 import { Response } from 'express';
-import { IRequest } from '@automatisch/types';
+import { IJSONObject, IRequest } from '@automatisch/types';
+import crypto from 'crypto';
+import { serialize } from 'php-serialize';
 import Billing from '../../helpers/billing/index.ee';
+import appConfig from '../../config/app';
 
 export default async (request: IRequest, response: Response) => {
-  const isVerified = Billing.paddleClient.verifyWebhookData(request.body);
-
-  if (!isVerified) {
+  if (!verifyWebhook(request)) {
     return response.sendStatus(401);
   }
 
@@ -17,3 +18,28 @@ export default async (request: IRequest, response: Response) => {
 
   return response.sendStatus(200);
 };
+
+const verifyWebhook = (request: IRequest) => {
+  const signature = request.body.p_signature;
+
+  const keys = Object.keys(request.body)
+    .filter((key) => key !== 'p_signature')
+    .sort();
+
+  const sorted: IJSONObject = {};
+  keys.forEach((key) => {
+    sorted[key] = request.body[key];
+  });
+
+  const serialized = serialize(sorted);
+
+  try {
+    const verifier = crypto.createVerify('sha1');
+    verifier.write(serialized);
+    verifier.end();
+
+    return verifier.verify(appConfig.paddlePublicKey, signature, 'base64');
+  } catch (err) {
+    return false;
+  }
+};