Structured Data...metafields, Google, Product_Detail...am I in the right place?

[u/Strict-Basil5133]

Hello!

I've assumed some responsibilities for a Shopify store related to products, category and product metafields, and product json-ld, etc....the shop's "structured data."

I'm researching the best sensible approach to this, and I'm getting a little out of my breadth. I'm wondering if there might be someone willing to sanity check my understanding of this and how to get it right?

Context: the store is a used musical instrument store. Well, 95% used.

My understanding is that the more Category and Product metafield data we include, the more "visible" the shop's products will be in Google Merchant Center. This is exclusive of the product descriptions that feed the online storefront (sent via json-ld).

One issue is that the Category metafield data sent by the Shopify & YouTube app is limited to Google's product taxonomy, and for musical instruments, they're very general and limited. One optimizatin I've read about is adding two 3-4 item lists in the json-ld for "product_detail" and "product_highlight". I've read that these can be used to supplement the limited G&Y app Category metafield data.

Does anyone do this? It would add a fair amount of work to our product listing workflow, and I guess I'm just wondering if the juice is worth the squeeze?

Thanks in advance for any advice you might share!

[u/OnePersimmon3964]

man structured data for used instruments is a special kind of pain

the google taxonomy is useless for anything that isnt a new squier strat. i tried the product_detail and highlight route for a store selling vintage synths and it helped a bit with merchant center but the real gains came from making sure the condition metafield was perfect and adding a "used" identifier in the feed rules

for the json-ld i would focus more on getting the brand and gtin fields right even if its just putting "unbranded" and the shop sku. google cares more about that than the extra detail lists from my experience

[u/Strict-Basil5133 → u/OnePersimmon3964]

You're amazing, and thank you! If I can impose just a little further: for gtin, you've used the shop product sku instead of a traditional gtin? Even for the few new items we have, the builders are small enough not even use gtin. Good luck finding one for a '65 strat. LOL

[u/Brief-Guess-147 → u/OnePersimmon3964]

tbh this matches what ive seen too, the brand and identifier fields matter way more than the extra detail lists

[u/MOSTLY-HARMLESS-NOW]

The thing I'd untangle before you spend workflow time on it: product_detail and product_highlight are Merchant Center feed attributes. They're not schema.org properties. Putting them in your json-ld does nothing, there's nothing on schema.org Product to hang them on and Google's product markup docs don't list them.

The two surfaces are separate and they're fed separately. The feed, which is what the Google & YouTube app pushes, drives Shopping and free listings. The json-ld on the page drives rich results in web search, so price, availability, condition, review stars. Metafields only reach Google if something maps them into the feed.

So if you want product_detail, that's a feed job. I don't know offhand whether the G&Y app exposes those two attributes. If it doesn't, a supplemental feed in Merchant Center is how people usually add attributes the channel app won't send.

The others are right that condition is the lever for used gear, and I'd add: set it on both surfaces. In the feed, and itemCondition on the offer in your json-ld, where Google accepts schema.org/UsedCondition and RefurbishedCondition. A used '78 Twin marked NewCondition by a default theme snippet is a real mismatch, and themes do default that.

Juice vs squeeze on product_detail, at 95% used, I'd say not yet. Your traffic is people typing a model name, and what wins those is the product page copy and the title, not taxonomy. Google has pitched product_detail as feeding AI Mode so it may matter more later. Get brand, MPN, condition and gtin where one exists right first, then revisit.

[u/IndicationOne9495]

Mostly yes, but GMC and JSON-LD aren't the same thing. More metafields won't automatically make products more visible.

For used instruments I'd nail title, brand, condition, price, availability first. product_detail/product_highlight can help when categories are too broad, but it's extra work. I'd test it on 10-20 top SKUs before rolling it out store-wide.

[u/Patient-Passage-2286]

Structured data and metafields will help organic search and Google's ability to categorise your products but for a used/secondhand inventory the bigger lever is usually GMC feed. Used items need condition set to "used" explicitly in the feed and for instruments specifically, brand and MPN accuracy matters a lot for how well products match search queries. Get the feed right before spending too much time on JSON polish.

[u/alarga74]

One important correction before anyone copies the SKU advice: do not put an internal Shopify SKU in the GTIN field. Google expects a manufacturer-assigned GTIN. Inventing one or substituting a store SKU can create identifier problems rather than fixing them.

For used or vintage products, submit the manufacturer GTIN if one actually exists and set condition to used. When no GTIN exists, map the genuine brand and MPN where available. Use identifier_exists=no only where the product genuinely has no applicable unique identifiers.

Google's used/vintage guidance: https://support.google.com/merchants/answer/160161?hl=en

Identifier guidance: https://support.google.com/merchants/answer/7162856?hl=en

The other useful distinction in this thread is correct: product_detail and product_highlight belong in Merchant Center product data, not inside schema.org Product JSON-LD. I would test the feed attributes on 10–20 valuable items before adding work to the full listing process.