diff --git a/src/lib/interfaces.ts b/src/lib/interfaces.ts
index b15cbe24..cba5aa9f 100644
--- a/src/lib/interfaces.ts
+++ b/src/lib/interfaces.ts
@@ -264,12 +264,12 @@ export interface KeyboardOptions {
     /**
      * Executes the callback function every time simple-keyboard is rendered (e.g: when you change layouts).
      */
-     onRender?: (instance?: SimpleKeyboard) => void;
+     onRender?: (instance: SimpleKeyboard) => void;
 
     /**
      * Executes the callback function once simple-keyboard is rendered for the first time (on initialization).
      */
-     onInit?: (instance?: SimpleKeyboard) => void;
+     onInit?: (instance: SimpleKeyboard) => void;
 
     /**
      * Retrieves the current input
@@ -295,4 +295,4 @@ export interface KeyboardOptions {
      * Module options can have any format
      */
     [name: string]: any;
-}
\ No newline at end of file
+}