diff --git a/src/MatrixClientPeg.ts b/src/MatrixClientPeg.ts
index e875a053b5..c6ee6c546f 100644
--- a/src/MatrixClientPeg.ts
+++ b/src/MatrixClientPeg.ts
@@ -41,7 +41,7 @@ export interface IMatrixClientCreds {
     deviceId: string,
     accessToken: string,
     guest: boolean,
-    pickleKey: string,
+    pickleKey?: string,
 }
 
 // TODO: Move this to the js-sdk