Hey @huykon225 - thanks for sharing the screenshot there.
Based on an “empty” loader that only runs authenticate.admin and the long “Waiting for server response” in prod, this seems like it may be infrastructure/TTFB-related (Fly) rather than a Polaris/App Bridge/Shopify library issue.
To confirm, I’d say adding Server‑Timing around authenticate.admin and then comparing TTFB vs content download in DevTools should confirm.
I can’t assist too much on my end with third party integrations, but just based on personal experience with Google Cloud, on Fly, you may want to check for cold starts/unpauses and see if your machines are set to auto-turn off based on low usage if that’s a possibility.
I’d also verify if your app and session store/DB are co-located in the same region since that can also sometimes affect performance.
I can’t go deep on Fly infrastructure from the Shopify side, but others here may be able to help if you share a HAR, response headers (including Server‑Timing), and the serving region. Alternatively, you can ask in our developer Slack as well if folks don’t respond here, I can DM you an invite if you’d like, just let me know!
