diff --git a/src/interfaces/backoff-opts.ts b/src/interfaces/backoff-opts.ts
index bc99cd5409..299390faf1 100644
--- a/src/interfaces/backoff-opts.ts
+++ b/src/interfaces/backoff-opts.ts
@@ -1,4 +1,4 @@
 export interface BackoffOpts {
   type: string;
-  delay: number;
+  delay?: number;
 }