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 c98f7367..862e92da 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
@@ -74,6 +74,13 @@ object ConfigIndexingActions {
         }
     }
 
+    @Suppress("UnusedPrivateMember")
+    private fun validateMattermostConfig(slack: Slack, user: User?) {
+        require(slack.url.contains(Regex("https://.*/hooks/.*"))) {
+            "Wrong webhook url. Should match \"https://.*/hooks/.*\""
+        }
+    }
+
     @Suppress("UnusedPrivateMember")
     private fun validateWebhookConfig(webhook: Webhook, user: User?) {
         // TODO: URL validation with rules
@@ -172,6 +179,7 @@ object ConfigIndexingActions {
             ConfigType.SLACK -> validateSlackConfig(config.configData as Slack, user)
             ConfigType.CHIME -> validateChimeConfig(config.configData as Chime, user)
             ConfigType.MICROSOFT_TEAMS -> validateMicrosoftTeamsConfig(config.configData as MicrosoftTeams, user)
+            ConfigType.MATTERMOST -> validateMattermostConfig(config.configData as Slack, user)
             ConfigType.WEBHOOK -> validateWebhookConfig(config.configData as Webhook, user)
             ConfigType.EMAIL -> validateEmailConfig(config.configData as Email, user)
             ConfigType.SMTP_ACCOUNT -> validateSmtpAccountConfig(config.configData as SmtpAccount, user)