diff --git a/docs/credential-helpers.md b/docs/credential-helpers.md
index d1869e1..719d11e 100644
--- a/docs/credential-helpers.md
+++ b/docs/credential-helpers.md
@@ -46,7 +46,7 @@ volumes:
 ```
 
 and for `<PATH_TO_HOME_DIR>/.docker/config.json`:
-```yaml
+```json
   {
     "HttpHeaders" : {
       "User-Agent" : "Docker-Client/19.03.1 (XXXXXX)"