diff --git a/.env.sample b/.env.sample
index 22679d8..c133fc8 100644
--- a/.env.sample
+++ b/.env.sample
@@ -37,6 +37,7 @@ FIREBASE_ADMIN_AUTH_URI=
 FIREBASE_ADMIN_TOKEN_URI=
 FIREBASE_ADMIN_AUTH_PROVIDER_X509_CERT_URL=
 FIREBASE_ADMIN_CLIENT_X509_CERT_URL=
+FIREBASE_ADMIN_UNIVERSE_DOMAIN=
 
 # stripe
 STRIPE_TEST_API_KEY=