diff --git a/.github/workflows/pr_preview.yml b/.github/workflows/pr_preview.yml
index 3dafc5a44..da9b372b8 100644
--- a/.github/workflows/pr_preview.yml
+++ b/.github/workflows/pr_preview.yml
@@ -290,7 +290,8 @@ jobs:
           fi
 
           # Define app URLs (used for secrets and outputs)
-          APP_DOMAIN="${APP_NAME}.fly.dev"
+          # Custom domain via Cloudflare Worker: {fly_app}-preview.mtcl.cc
+          APP_DOMAIN="${APP_NAME}-preview.mtcl.cc"
           PUBLIC_APP_URL="https://${APP_DOMAIN}"
 
           # Set all secrets and environment variables for the app
@@ -474,3 +475,4 @@ jobs:
 
             ---
             *Cleanup triggered by PR close at ${{ github.event.pull_request.closed_at || 'N/A' }}*
+