diff --git a/src/MongoDB.ts b/src/MongoDB.ts
index 0ae995f..b96e197 100644
--- a/src/MongoDB.ts
+++ b/src/MongoDB.ts
@@ -1,5 +1,5 @@
 import { inspect } from "node:util";
-import { MongoClient, MongoClientOptions, Db, Document, WithId, ObjectId, Filter } from "mongodb";
+import { MongoClient, MongoClientOptions, Db, Document, WithId, ObjectId, Filter, IndexSpecification } from "mongodb";
 import { IServer, ILogger, LoggerClientOptions } from "./interfaces/index.js";
 
 type Credentials = {
@@ -327,7 +327,7 @@ class MongoDB {
         return this.#db.collection(coll);
     }
 
-    async ensureIndex (collection: string, indices: string[] = []) {
+    async ensureIndex (collection: string, indices: IndexSpecification = []) {
         if (!this.#db) 
             throw new Error(`MongoDB not connected`);
         if (!(indices instanceof Array))