diff --git a/src/main/java/vercel/VercelMPIdentityProvider.java b/src/main/java/vercel/VercelMPIdentityProvider.java
index b283557..0a2113f 100755
--- a/src/main/java/vercel/VercelMPIdentityProvider.java
+++ b/src/main/java/vercel/VercelMPIdentityProvider.java
@@ -40,6 +40,7 @@
 
 public class VercelMPIdentityProvider extends OIDCIdentityProvider implements SocialIdentityProvider<OIDCIdentityProviderConfig> {
     private static final String BROKER_NONCE_PARAM = "BROKER_NONCE";
+    private static final String EMAIL_FALLBACK_TEMPLATE = "%s@vercelmp.internal";
 
     private static final Logger logger = Logger.getLogger(VercelMPIdentityProvider.class);
     //private static final String AUTH_URL = "https://api.vercel.com/oauth/authorize";
@@ -152,7 +153,7 @@ protected BrokeredIdentityContext extractIdentity(AccessTokenResponse tokenRespo
         String userIdPerInstallation = (String) idToken.getOtherClaims().get("user_id")
 
         if (email == null || email.isEmpty()) {
-            email = userIdPerInstallation + "@vercel-marketplace.com";
+            email = EMAIL_FALLBACK_TEMPLATE.formatted(userIdPerInstallation);
         }
         // Global user ID is provided by Vercel only for Neon integrations!
         // For other marketplace integrations it provides only user ID per each integration installation.