diff --git a/stack.production.yml b/stack.production.yml
index 9a0c4fd..86b3a1e 100644
--- a/stack.production.yml
+++ b/stack.production.yml
@@ -25,6 +25,7 @@ services:
       # SMTP_TLS: always
       SMTP_PASSWORD: "DiHcwSup8RSo66LgEzGi7R4PBWsDyFgxn"
       UNCLAIMED_RECORDING_TTL: "30"
+      SIGN_UP_DISABLED: "true"
     volumes:
       - /mnt/tank/persist/nixc.us/asciinema/production/data:/var/opt/asciinema
     deploy: