diff --git a/src/actions/push-notifications/registerer.ts b/src/actions/push-notifications/registerer.ts
index 48a0bc8fd..9937fd938 100644
--- a/src/actions/push-notifications/registerer.ts
+++ b/src/actions/push-notifications/registerer.ts
@@ -45,7 +45,7 @@ const unsubscribe = ({ registration, subscription }: {
 const sendSubscriptionToBackend = (subscription: PushSubscription, me: Me) =>
   (dispatch: AppDispatch, getState: () => RootState) => {
     const alerts = getState().push_notifications.alerts.toJS();
-    const params = { subscription, data: { alerts } };
+    const params = { subscription: subscription.toJSON(), data: { alerts } };
 
     if (me) {
       const data = pushNotificationsSetting.get(me);
@@ -54,7 +54,7 @@ const sendSubscriptionToBackend = (subscription: PushSubscription, me: Me) =>
       }
     }
 
-    return dispatch(createPushSubscription(params) as any);
+    return dispatch(createPushSubscription(params));
   };
 
 // Last one checks for payload support: https://web-push-book.gauntface.com/chapter-06/01-non-standards-browsers/#no-payload
diff --git a/src/actions/push-subscriptions.ts b/src/actions/push-subscriptions.ts
index b370c5045..19b047950 100644
--- a/src/actions/push-subscriptions.ts
+++ b/src/actions/push-subscriptions.ts
@@ -18,7 +18,15 @@ const PUSH_SUBSCRIPTION_DELETE_FAIL    = 'PUSH_SUBSCRIPTION_DELETE_FAIL';
 
 import type { AppDispatch, RootState } from 'soapbox/store';
 
-const createPushSubscription = (params: Record<string, any>) =>
+interface CreatePushSubscriptionParams {
+  subscription: PushSubscriptionJSON;
+  data?: {
+    alerts?: Record<string, boolean>;
+    policy?: 'all' | 'followed' | 'follower' | 'none';
+  };
+}
+
+const createPushSubscription = (params: CreatePushSubscriptionParams) =>
   (dispatch: AppDispatch, getState: () => RootState) => {
     dispatch({ type: PUSH_SUBSCRIPTION_CREATE_REQUEST, params });
     return api(getState).post('/api/v1/push/subscription', params).then(({ data: subscription }) =>