diff --git a/src/typebox.ts b/src/typebox.ts
index 75929bcf..bb767752 100644
--- a/src/typebox.ts
+++ b/src/typebox.ts
@@ -65,6 +65,7 @@ export type AssertType<T, E extends TSchema = TSchema> = T extends E ? T : TNeve
 // --------------------------------------------------------------------------
 // Modifiers
 // --------------------------------------------------------------------------
+export type TModifier = TOptional<TSchema> | TReadonly<TSchema>
 export type TReadonly<T extends TSchema> = T & { [Readonly]: 'Readonly' }
 export type TOptional<T extends TSchema> = T & { [Optional]: 'Optional' }
 // --------------------------------------------------------------------------