App proxy issue in theme extension

Shopify App Store
1

Developing a theme extension. When trying to call my API via proxy, it giving 404, no logs find on API server. If I call the API directly without any proxy, it works fine.

.toml file
[access_scopes]

scopes = “write_products,write_app_proxy”
[app_proxy]
url = “https://domain.com”
subpath = “vir_ton”
prefix = “apps”

js file

const resp = await fetch(“/apps/vir_ton/get_token”, {
method: ‘POST’,
headers: { ‘Content-Type’: ‘application/json’ },
credentials: ‘same-origin’
});

Shopify error log

ErrorResponseImpl {
12:06:43 │ React Router │ status: 404,
12:06:43 │ React Router │ statusText: ‘Not Found’,
12:06:43 │ React Router │ internal: true,
12:06:43 │ React Router │ data: ‘Error: No route matches URL “/get_token”’,
12:06:43 │ React Router │ error: Error: No route matches URL “/get_token”

Any idea to resolve the same

2

In my debugging, its looking like the proxy url calls the ngrok proxy instaed of app proxy url. I am using ngrok tunneling to run the shopify app locally. Any solution for this

3

Hi @JOSEPH_ALEXANDER –

At the moment, the automatically_update_urls_on_dev setting is all-or-nothing for your App URL, Redirect URLs, and App Proxy URL.

If your App Proxy is at a different host, the common workaround is to use a static URL during development (such as a paid ngrok account), and disabling this setting in your app toml.

4

Hi @NickWesselman
Thank you for your reply.
I am using a static domain for the API hosting and Shopify running via ngrok tunneling. The proxy requests not reaching the API server.

5

Can you post your app toml? Have you tried disabling automatically_update_urls_on_dev?

6

Hi @NickWesselman

client_id = “######5feb4”
name = “V#####on”
application_url = “https://example.com”
embedded = true

[build]
automatically_update_urls_on_dev = true
include_config_on_deploy = true

[webhooks]
api_version = “2026-01”

[[webhooks.subscriptions]]
topics = [ “app/uninstalled” ]
uri = “/webhooks/app/uninstalled”

[[webhooks.subscriptions]]
topics = [ “app/scopes_update” ]
uri = “/webhooks/app/scopes_update”

[access_scopes]

scopes = “write_products,write_app_proxy”

[auth]
redirect_urls = [ “https://example.com/api/auth” ]
[app_proxy]
url = “https://3333.net.in”
subpath = “virtual_tryon”
prefix = “apps”

1 Like
7

That worked. Thank you so much