diff --git a/config/packages/nelmio_security.yaml b/config/packages/nelmio_security.yaml
index 24e0a50d..d97b3983 100644
--- a/config/packages/nelmio_security.yaml
+++ b/config/packages/nelmio_security.yaml
@@ -58,3 +58,9 @@ nelmio_security:
                 - 'data:'
             block-all-mixed-content: true # defaults to false, blocks HTTP content over HTTPS transport
             # upgrade-insecure-requests: true # defaults to false, upgrades HTTP requests to HTTPS transport
+
+when@dev:
+    # disables the Content-Security-Policy header
+    nelmio_security:
+        csp:
+            enabled: false
\ No newline at end of file