Fixing JSON-LD Errors in Shopify

Where Shopify JSON-LD comes from

Shopify itself does not inject structured data into your storefront. Everything you see comes from the theme or from code added to it, directly or through an app.

The structured_data filter is convenient because Shopify keeps its output in line with the product data, but you cannot edit what it prints. If it omits something you need, the choice is to supplement it with a separate block that shares the same @id, or to replace it with your own Liquid.

Tracing a block back to its file or app

The JSON Checker lists every block it found on the page. To connect each one to its source:

1. Compare view source with the rendered page. Blocks present in view source (Ctrl+U) come from Liquid, so they live in the theme or an app embed. Blocks that only appear in the developer tools Elements panel were added by JavaScript.
2. Search the theme code. In the admin go to Online Store, Themes, then the three-dot menu on your theme and Edit code. Use the search to find ld+json and structured_data. Each hit is a candidate; compare its property names with the block on the page.
3. Toggle app embeds. In the theme editor, open App embeds and switch off one embed at a time on a copy of the theme, then preview a product page. The block that disappears belongs to that app.
4. Look for app fingerprints. App output often carries an id or class on the script element, a comment naming the app, or property values only that app would add, such as a review count.
5. Check for leftovers. Apps that edited theme files directly, rather than using app embeds, can leave {% render %} tags and snippets behind after you uninstall them. A block from an app you no longer use is almost always one of these.

The Shopify faults behind most findings

A safe Liquid pattern for a custom Product block

If you replace the theme's output with your own, build every value through the json filter and print optional properties only when they have a value. This snippet is a starting point for a store selling in one currency with simple variants. Save it as a snippet and render it once from the main product section.

{%- assign v = product.selected_or_first_available_variant -%}
<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Product",
  "@id": {{ canonical_url | append: '#product' | json }},
  "name": {{ product.title | json }},
  "url": {{ canonical_url | json }},
  {%- if product.featured_image %}
  "image": {{ product.featured_image | image_url: width: 1200 | prepend: 'https:' | json }},
  {%- endif %}
  "description": {{ product.description | strip_html | truncate: 500 | json }},
  {%- if v.sku != blank %}
  "sku": {{ v.sku | json }},
  {%- endif %}
  {%- if product.vendor != blank %}
  "brand": { "@type": "Brand", "name": {{ product.vendor | json }} },
  {%- endif %}
  "offers": {
    "@type": "Offer",
    "url": {{ shop.url | append: v.url | json }},
    "price": {{ v.price | divided_by: 100.0 | json }},
    "priceCurrency": {{ cart.currency.iso_code | json }},
    "availability": "https://schema.org/{% if v.available %}InStock{% else %}OutOfStock{% endif %}"
  }
}
</script>

Each optional property ends with a comma and is followed by a property that always prints, so a skipped value never leaves a trailing comma. Rendered for a real product, the output looks like this and parses cleanly:

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Product",
  "@id": "https://www.example.co.uk/products/glazed-planter-12#product",
  "name": "Glazed planter 12\" sage",
  "url": "https://www.example.co.uk/products/glazed-planter-12",
  "image": "https://www.example.co.uk/cdn/shop/files/planter-sage.jpg?width=1200",
  "description": "Frost-resistant stoneware planter with drainage hole.",
  "sku": "GP-12-SAGE",
  "brand": { "@type": "Brand", "name": "Hollowmere Pottery" },
  "offers": {
    "@type": "Offer",
    "url": "https://www.example.co.uk/products/glazed-planter-12?variant=40123456789",
    "price": 34.0,
    "priceCurrency": "GBP",
    "availability": "https://schema.org/InStock"
  }
}
</script>

Apps, leftovers and theme updates

Apps are the most common reason a Shopify page carries markup nobody on the team wrote. Keep these points in mind:

• Review apps often add AggregateRating and Review either as their own Product block or by merging into the theme's. If the theme block and the app block both describe the product, pick one to own the Product and let the other add only ratings, using the same @id. Many review apps have a setting for this.
• SEO and schema apps usually offer toggles per type. If you turn on their Product markup, turn off the theme's, and the other way round.
• Uninstalled apps that edited theme files leave code behind. Search the theme for the app's name and for snippets you do not recognise, and remove the render tags as well as the snippet files.
• Theme updates install a fresh copy of the theme. Custom edits inside theme files do not carry over automatically, so a fix made in main-product.liquid can vanish. Keep custom markup in its own snippet with a clear name, and note every file you changed.

How to decide which of two competing blocks should win is covered in the competing schemas guide. This page is about finding and repairing them on Shopify.

The fix, step by step

Variants, Markets and other edge cases

• Variant URLs. When a shopper picks a variant, the URL gains ?variant= and the visible price may change. The markup rendered by Liquid reflects the variant selected when the page was served, so link the offer to the variant URL it describes.
• Many variants. For products with several sizes or colours, a single Offer for the first available variant is acceptable but incomplete. Describing each variant needs a ProductGroup structure; plan that as a separate piece of work.
• Markets and currencies. With several markets, prices and currency change with the shopper's country. Reading price and currency from the same Liquid objects keeps them consistent; a hard-coded currency is the usual cause of mismatches.
• Password-protected stores. While the storefront password is on, crawlers cannot reach the pages at all. Test through theme preview, and expect Search Console reports only after launch.
• Headless storefronts. If the store runs on Hydrogen or another framework, the markup lives in that codebase, not in Liquid, and the theme advice here does not apply.