diff --git a/lib/jwt/ClientCapability.d.ts b/lib/jwt/ClientCapability.d.ts
index c613698239..bec2298a0c 100644
--- a/lib/jwt/ClientCapability.d.ts
+++ b/lib/jwt/ClientCapability.d.ts
@@ -47,7 +47,7 @@ declare namespace ClientCapability {
   export interface ClientCapabilityOptions {
     accountSid: string;
     authToken: string;
-    ttl: number;
+    ttl?: number;
   }
 }