diff --git a/composer.json b/composer.json
index 24a5a8e4f..c7513cc79 100644
--- a/composer.json
+++ b/composer.json
@@ -55,7 +55,8 @@
     "require-dev": {
         "phpunit/phpunit": "^5.7",
         "sminnee/phpunit-mock-objects": "^3.4.5",
-        "silverstripe/versioned": "^1"
+        "silverstripe/versioned": "^1",
+        "squizlabs/php_codesniffer": "^3.5"
     },
     "provide": {
         "psr/container-implementation": "1.0.0"
@@ -104,4 +105,4 @@
     },
     "minimum-stability": "dev",
     "prefer-stable": true
-}
\ No newline at end of file
+}