diff --git a/backend/src/app/config.clj b/backend/src/app/config.clj
index 79972b2c9..18a5e2e75 100644
--- a/backend/src/app/config.clj
+++ b/backend/src/app/config.clj
@@ -83,7 +83,7 @@
    ;; a server prop key where initial project is stored.
    :initial-project-skey "initial-project"})
 
-(s/def ::flags ::us/set-of-keywords)
+(s/def ::flags ::us/vec-of-keywords)
 
 ;; DEPRECATED PROPERTIES
 (s/def ::registration-enabled ::us/boolean)