App Proxy returns Shopify 404 (Next.js backend + Theme App Extension + ngrok) — backend works directly but proxy never hits server

Extensions
1

Hi everyone,

I’m stuck with App Proxy and not sure what I’m missing.

Setup:

Frontend call:
fetch(‘/apps/spubp/proxy_route/reviews’)

Backend route (Next.js App Router):
app/api/proxy_route/reviews/route.ts

Works directly via pagekite:
https://<pagekite-url>/api/proxy_route/reviews

Issue:

  • /apps/spubp/proxy_route/reviews returns Shopify 404
  • even when I point proxy to https://httpbin.org, still 404
  • backend logs show nothing → request never reaches server

Not sure what I’m missing here — app is installed and proxy config looks correct.

Here is the screenshot of the app proxy

image
image918×152 4.17 KB

Anyone seen this before?

Thank you in advance.

2

Hi @BhuwanRai ,

Do you see the App Proxy URL details in Shopify Admin of your dev store?

You should be able to go to Shopify Admin > Settings > Apps > Your App > then scroll towards the bottom and you should see something like this:

Screenshot 2026-05-01 161231
Screenshot 2026-05-01 1612311466×294 15.4 KB

Do you see this?

3

Hi @adamwooding

Thank you for calling this out. Its strange that even when i deploy the app, it did not set the app proxy properly. And interesting thing is that i did not have to make any change to the Shopify Admin as well, it started working when i just opened the customize url section.

image

Do you have any idea if i have to make some extra app proxy configuration before going to live except deploying it?

And once again, thank you so much for your reply and help.

Really Appreciated,
Bhuwan Rai