diff --git a/composer.json b/composer.json
index 0e02fa2..7f67e77 100644
--- a/composer.json
+++ b/composer.json
@@ -30,7 +30,8 @@
         "omnipay/common": "^3.0"
     },
     "require-dev": {
-        "omnipay/tests": "^3.0"
+        "omnipay/tests": "^3.0",
+        "squizlabs/php_codesniffer": "^3.2"
     },
     "extra": {
         "branch-alias": {