Shopify app block
not appearing.

Symptoms

• App block missing from Add block menu: the app is installed and visible in the Apps admin, but its block never appears as an option when adding a block to a section.
• App embed list is empty: Theme settings → App embeds shows no entries, or shows the app but the toggle is off.
• Block shows in some sections but not others:addable inside the default Dawn/Horizon section but absent from a custom section a developer built.
• Block shows on one template but not another:available on the product page but missing on home or collection.
• Block disappeared after a theme duplicate: was working on the previous theme; not present on the new one.

2-minute diagnostic checklist

Run these five checks in order. Most cases resolve at step 2 (app embed toggle off) or step 4 (template scope). If you reach the end without the block appearing, it's either cause #3 (section schema) or cause #5 (wrong theme).

1. 01
   Confirm you're editing the active theme.

   Open Theme Customizer. Check the theme name at the top. Is it the published/active theme, or a duplicate? App installations are scoped per-theme, so a duplicate won't have the app extension installed.

2. 02
   Check the App embeds panel.

   Theme settings → App embeds. Confirm the app appears in the list and its toggle is on. Many app blocks are inert until this toggle is enabled. Flipping it on resolves the most common case.

3. 03
   Try Add block in the page template.

   Open the template you expect the block on (product, home, collection). Click the section you want the block inside. Click Add block. Look for the app block in the list.

4. 04
   If absent, switch templates and try again.

   Switch to a different template (e.g. from home to product) and repeat step 3. If the block now appears, the extension is scope-restricted (cause #4). The app's TOML declares which templates it's available on.

5. 05
   Verify the app is loading on the storefront.

   Open a live page on the storefront. View source (right-click → View page source) and search for the app's script handle or domain. If absent, the app embed isn't loading, usually because it's installed on a different theme (cause #5).

Most likely causes, ranked

1. 01
   App embed not enabled.

   Many app blocks require an "App embed" toggle in Theme Customizer → Theme settings → App embeds. Until that toggle is on, the app's section and block targets are inert and the merchant sees nothing in the Add block menu. Frequency: most common.

   Fix: open Customizer → Theme settings → App embeds → flip the toggle for the app. Save. Re-open the page template and try Add block again. The block should now appear.

2. 02
   Block target mismatch in extension TOML.

   The app extension's target (header / body / footer / section) doesn't match where the merchant is trying to add it. A body-target block won't appear in the header section's Add block menu even when the app embed is on.

   Fix: check the app's documentation for which sections support the block. If it's a body-only block, add it to a body section (e.g. main-product), not the header or footer. If you control the extension, update the target in the block's TOML.

3. 03
   Section schema missing { "type": "@app" }.

   For an app block to be addable inside a custom or third-party section, that section's schema blocks array must include { "type": "@app" }. Default Dawn and Horizon sections include it; older or custom themes often don't.

   Fix: open the section file (e.g. sections/your-section.liquid) and add the @app entry to the schema's blocks array. Patch shown in the Fix section below. This is the only cause that requires editing code.

4. 04
   Extension scoped to specific templates.

   The app's extension TOML restricts the block to e.g. templates = ["product"]. Trying to add it on the home or collection template silently fails. the block is hidden from the Add block menu rather than showing as disabled.

   Fix: check the app's docs for supported templates. Use the block on a supported template, or, if you own the extension, broaden the templates array in the block's TOML.

5. 05
   App installed on a different theme.

   Shopify scopes app installations per-theme. After duplicating a theme or restoring a backup, app theme extensions don't carry over to the new theme. The app shows in the Apps admin but its blocks are absent from the active theme.

   Fix: open the app's listing in Apps, find the "Add to theme" or "Install" button (most apps surface this once they detect a theme-extension mismatch), and re-install on the active theme. Save. Re-open Customizer.

Section schema patch (cause #3)

Only relevant when the merchant is trying to add the app block inside a custom section that doesn't already accept app blocks. The patch is one entry: { "type": "@app" }, added to the section schema's blocks array. Filename below is illustrative; edit your actual section file.

{% comment %}
  Jelonyx · Section schema patch: accept app blocks
  Add { "type": "@app" } to the section's blocks array so installed
  app extensions can be added inside this section.
  Source: jelonyx.com/shopify/fix/app-block-not-appearing
{% endcomment %}

{% schema %}
{
  "name": "Your section",
  "settings": [],
  "blocks": [
    {
      "type": "feature",
      "name": "Feature",
      "settings": []
    }

    /* ---------- BEFORE ----------
       blocks array stops here.
       Result: app blocks never show in the Add block menu
       for this section, even when the app embed is on.
    -------------------------------- */

    /* ---------- AFTER ----------
       Add the @app entry below. Comma after the previous
       block object, then the @app object. No settings, no
       name; Shopify treats it as a marker that this section
       accepts any installed app block whose target matches.
    -------------------------------- */
    ,
    { "type": "@app" }
  ],
  "presets": [
    { "name": "Your section" }
  ]
}
{% endschema %}

After saving, reload the Customizer. The section now accepts any installed app block whose target matches. and the block appears in the Add block menu.

When to call a developer

• You own the app extension: debugging the TOML target, templates, and stylesheet directives, plus the extension build pipeline, is faster with someone who's shipped a theme app extension before.
• The app vendor is unresponsive and you need a workaround (replicating the block's output in custom Liquid while you wait, or migrating to a different app).
• App embed loads but breaks layout: the toggle is on, the block renders, but it injects CSS or JS that conflicts with the theme. Different fix; this page covers non-appearance.
• Multi-theme rollout: you maintain several themes (live, staging, seasonal) and need each one configured with the same app embeds and blocks consistently.