App Store submission blocked: "Use theme app extensions" check failing

Extensions
1

Shopify App Store submission issue
Theme App Extension detection failing

Hi everyone,

I’m preparing to submit my Shopify app “Echo Bundle” to the App Store, but my submission is currently blocked by the Online Store app check:

Use theme app extensions

The issue is that my app already uses a Theme App Extension, but the automated check still fails.

Theme extension structure

extensions/theme-extension/
  assets/
  blocks/
    app-embed.liquid
    echo-bundle.liquid
  shopify.extension.toml

shopify.extension.toml

name = "Echo Bundle Theme Extension"
type = "theme"

App embed block

{% schema %}
{
  "name": "Bundle embed",
  "target": "body",
  "settings": [],
  "stylesheet": "echo-bundle.css",
  "javascript": "echo-bundle.js"
}
{% endschema %}

App block

{% schema %}
{
  "name": "Bundle block",
  "target": "section",
  "settings": [],
  "stylesheet": "echo-bundle.css",
  "javascript": "echo-bundle.js"
}
{% endschema %}
2

Have you deployed and released the app as part of an app version @Ronnie ?

After deploying, go to your app in the Partner Dashboard → Versions. You should see your latest version listed with the theme extension included. If the extension isn’t showing up there, the automated check won’t pass.

3

Hey, I’ve run into this exact check before and it’s almost always one of two things rather than an actual problem with your extension code.

First one to look at is your shopify.extension.toml. The flat format you posted with just name and type is the older structure. The current Shopify CLI expects the [[extensions]] array format with a handle field and api_version at the top level. Something like:

api_version = "2025-10"

[[extensions]]
name = "Echo Bundle Theme Extension"
handle = "echo-bundle-theme-extension"
type = "theme"

Without handle and api_version, the CLI might deploy the extension but the app review system can still flag it as missing. Shopify’s docs on extension configuration cover the full field list ( Configure app extensions ).

Second thing, and this is the one that catches most people, the check doesn’t just look at whether you have a theme extension in your project. It verifies that the extension was actually deployed through shopify app deploy and that the released app version includes it. If you’ve been running shopify app dev locally but never did a full deploy, the review system won’t see the extension at all. Run shopify app deploy and make sure the version that gets created shows the theme extension in the deploy output. Also double check that your app isn’t still using the ScriptTag API anywhere, even in a single route or legacy controler, because the check will fail if it detects ScriptTag usage alongside the theme extension. I see this come up pretty often with clients at Stacksync who are migrating older Shopify integrations and forget to remove a leftover ScriptTag call. The Shopify docs on ScriptTag deprecation explain this requirement in more detail ( The ScriptTag resource (legacy) ).

If both of those look fine and the check still fails, reach out to Shopify Partner support with your app ID and the deploy version nmber, they can manually verify on their end.

Hope this helps.

4

The issue resolved automatically and I was able to submit the app successfully.
Really appreciate the support!

5

I was able to submit the app successfully.
Really appreciate the support!