diff --git a/src/index.ts b/src/index.ts
index b9873ab..688d950 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -8,6 +8,7 @@ export { twMerge } from './lib/tw-merge'
 export {
     type ClassValidator,
     type Config,
+    type ConfigExtension,
     type DefaultClassGroupIds,
     type DefaultThemeGroupIds,
     type ExperimentalParseClassNameParam,