diff --git a/frontend/src/types.ts b/frontend/src/types.ts
index 2c0ae90..5fb8078 100644
--- a/frontend/src/types.ts
+++ b/frontend/src/types.ts
@@ -183,7 +183,7 @@ export type Tag = {
     createdAt:      string
     updatedAt:      string
     hasWiki:        boolean
-    materialId:     number
+    materialId:     number | null
     hasDeerjikists: boolean
     children?:      Tag[]
     matchedAlias?:  string | null }