Star ratings on Shopify product and collection pages

Stars on a Shopify store come from two different places, and knowing which one you are looking at saves a lot of guessing.

Kudo writes two values onto each product it has published reviews for: the average rating, and how many reviews it is an average of. These are Shopify's own standard rating metafields, in the reserved reviews namespace — the same two fields every rating app writes, and the ones Search & Discovery, filter apps and recommendation sections read. Nothing about them is specific to Kudo, so if you ever switch apps the fields stay where they are.

Product pages: no code

Switch on the Kudo app embed in your theme editor, under Theme settings → App embeds (the button on the Widgets page opens it for you). On every product page it adds the reviews under the product and a star rating next to its title. If you prefer to place things yourself, the Kudo star badge block does the rating alone: on a product template it draws that product's rating; anywhere else — a homepage, a collection header — it draws the whole store's.

No file is edited and nothing is pasted.

Collection pages: no code, with the app embed

The same app embed puts a small star row under the title of each product card on collection pages, search results and the homepage. Its setting is called Show stars on product grids, and it is on by default.

It makes no request. While Shopify builds the page, the embed reads the two rating metafields for the products on that page and writes them into the page itself; a few lines of script then add the stars to the matching cards. A product with no reviews shows nothing, and a card that already shows a rating — from your theme, or from the snippet below — is left alone, so stars never appear twice.

What it covers, stated plainly:

• Collection pages: the first 50 products of the collection in the order shown. That is the whole first page on any theme showing 50 or fewer products per page.
• Search results: products among the first 50 results.
• The homepage: your store's first 50 products. If you have more than 50, a featured collection is covered only where it overlaps those.
• Not covered: "You may also like" rows on product pages, and products past the first 50 that a theme loads later by infinite scroll or a filter.

If your theme's cards are not recognised, enter the CSS class of one product card (for example .card-wrapper) in the embed's Product card element setting.

The fallback: one line of theme code

A product card in a grid is rendered by a snippet the theme owns, and Dawn — like most themes built on the current Shopify architecture — does not accept app blocks inside that card. That is why the app embed adds the stars by script. Where it cannot find your cards, or for products past the first 50, Kudo ships a snippet you add to the card yourself. It makes no request at all: it reads the two metafields and Shopify renders it on the server with the rest of the page.

1. Duplicate your theme first. A product-card snippet is on every collection page in the store, so preview before publishing.
2. In the theme editor, open the three-dot menu and choose Edit code.
3. Under Snippets, add a new snippet named kudo-stars, and paste in the file Kudo gives you on the Widgets screen. It is ordinary Liquid.
4. Open the snippet that renders your product card — in Dawn that is snippets/card-product.liquid — and add one line where the stars should go, usually just under the title: render kudo-stars with product: card_product, written in Liquid render tags.
5. Preview, then publish.

The name of the variable holding the product changes from theme to theme. Dawn calls it card_product; others use product or card.product. If nothing appears, that name is the first thing to check.

Why the app cannot paste the snippet for you

Shopify only allows an app's own blocks to render that app's snippets. A snippet used inside a theme's own product card has to live in the theme, which means the file is yours and Kudo cannot install it. That is a platform rule rather than a decision on our side, and it applies to every reviews app equally. The app embed exists so that most stores never need it.

Stars in Google Shopping

Ratings on your own store are one surface; ratings beside your products in Google Shopping are another. Kudo can produce the review feed Google Merchant Center reads, which is what puts stars on a shopping result before anyone visits your site.

Only reviews attached to a product go into that feed. A review about your business as a whole does not describe any product, so filing it against one would be misattribution — and the penalty for that lands on your Merchant Center account, not on ours.

When stars do not appear

The product has no published reviews yet. The metafields are only written for products that have some. A review still waiting in your approval queue does not count.

The review is not attached to a product. Reviews collected through your general review link describe the business, not an item. Product reviews come from the product-specific link, which Kudo builds for you.

The app embed is off, or its grid setting is unticked. Check Theme settings → App embeds in the theme editor.

The product is past the first 50 on that page, or the embed did not recognise your cards. Set Product card element in the embed, or use the snippet for those cards.

The theme does not read the metafields. Most current themes do, but not all. If the star badge block works on the product page and your own card edit does not, the variable name in step 4 is the usual cause.

It has been less than a few minutes. Ratings are updated in batches rather than on every single review, so a change is not instant.

Frequently asked questions

Which metafields does Kudo write?
The two standard ones in Shopify's reviews namespace: the rating and the rating count. They are the same fields other rating apps use, so switching apps later does not orphan them.

Do I need a paid plan for this?
No. Publishing reviews and showing them on your store works on Free, with four of the thirteen widget layouts and the star rating badge beside the price. Pro adds the other layouts, removes the Powered by Kudo line, and publishes every review rather than 5.

Can I get stars on collection pages without touching code?
Yes. Switch on the Kudo app embed and leave Show stars on product grids ticked. It covers the first 50 products on collection pages, search results and the homepage. The one-line snippet is only for cards the embed cannot find or reach.

Do I have to edit my theme code for product card stars?
Not usually. The app embed adds them without any code. The snippet edit is the fallback for themes whose cards it does not recognise, and for products beyond the first 50 on a page.

Do these stars slow my store down?
No. Neither the app embed nor the snippet downloads anything: the ratings come with the page Shopify already sends, and no widget is loaded per card. The embed adds its star row with a few lines of script after the cards appear, which can move a card by one short line as the page first draws.

Will my ratings survive if I stop using Kudo?
The metafields stay on your products as they were last written. They do not keep updating, because nothing is left to update them.

Still stuck? Write to support@getkudo.co with your store address and which page is missing stars.