diff --git a/web/src/lib/billing-client.ts b/web/src/lib/billing-client.ts
index 7ff0cd1..2860ce1 100644
--- a/web/src/lib/billing-client.ts
+++ b/web/src/lib/billing-client.ts
@@ -50,13 +50,13 @@ function toSubscription(doc: SubscriptionDoc): Subscription {
     userId: doc.userId,
     plan: doc.plan as Subscription['plan'],
     status: doc.status as Subscription['status'],
-    currentPeriodStart: doc.currentPeriodStart,
+    currentPeriodStart: doc.currentPeriodStart ?? '',
     currentPeriodEnd: doc.currentPeriodEnd,
     cancelAtPeriodEnd: doc.cancelAtPeriodEnd,
     stripeCustomerId: doc.stripeCustomerId,
     stripeSubscriptionId: doc.stripeSubscriptionId,
-    createdAt: doc.createdAt,
-    updatedAt: doc.updatedAt,
+    createdAt: doc.createdAt ?? '',
+    updatedAt: doc.updatedAt ?? '',
   };
 }