diff --git a/src/ol/transformfunction.js b/src/ol/transformfunction.js
index fe7cb3fed4..d734d241fd 100644
--- a/src/ol/transformfunction.js
+++ b/src/ol/transformfunction.js
@@ -8,6 +8,6 @@ goog.provide('ol.TransformFunction');
  * returns the output array.
  *
  * @typedef {function(Array.<number>, Array.<number>=, number=): Array.<number>}
- * @api
+ * @api stable
  */
 ol.TransformFunction;