diff --git a/packages/redux-devtools/src/persistState.ts b/packages/redux-devtools/src/persistState.ts
index f0717df7..d89ca383 100644
--- a/packages/redux-devtools/src/persistState.ts
+++ b/packages/redux-devtools/src/persistState.ts
@@ -8,7 +8,7 @@ export default function persistState<
   A extends Action<unknown>,
   MonitorState
 >(
-  sessionId: string | null | undefined,
+  sessionId?: string | null,
   deserializeState: (state: S) => S = identity,
   deserializeAction: (action: A) => A = identity
 ): StoreEnhancer {