diff --git a/notifications/notifications/src/main/kotlin/org/opensearch/notifications/index/ConfigIndexingActions.kt b/notifications/notifications/src/main/kotlin/org/opensearch/notifications/index/ConfigIndexingActions.kt
index 2ef5b93a..bf0a3293 100644
--- a/notifications/notifications/src/main/kotlin/org/opensearch/notifications/index/ConfigIndexingActions.kt
+++ b/notifications/notifications/src/main/kotlin/org/opensearch/notifications/index/ConfigIndexingActions.kt
@@ -56,7 +56,9 @@ object ConfigIndexingActions {
 
     @Suppress("UnusedPrivateMember")
     private fun validateSlackConfig(slack: Slack, user: User?) {
-        // TODO: URL validation with rules
+        require(slack.url.contains(Regex("https://hooks\\.slack\\.com/services"))) {
+            "Wrong Slack url. Should contain \"hooks.slack.com/services/\""
+        }
     }
 
     @Suppress("UnusedPrivateMember")