Optimization Guide

Shopify Pre-Owned & Resale Product Schema — itemCondition, Authentication & Condition Grade JSON-LD

Q: What are the itemCondition values for used and refurbished products?

Schema.org defines five itemCondition enum values for Offer: NewCondition (brand new, never used), UsedCondition (previously owned, any grade), RefurbishedCondition (professionally restored to working order), DamagedCondition (sold as-is with known damage), and OldCondition (antique or vintage designation). Set these on the Offer object, not on the Product root. For pre-owned/resale stores, the most important is UsedCondition. Always pair itemCondition with an additionalProperty 'conditionGrade' string (Like New, Excellent, Very Good, Good, Fair, Poor) to give AI agents the sub-classification they need for queries like 'pre-owned MacBook excellent condition' or 'used Lululemon leggings like new'.

Q: How do I express a luxury authentication certificate in schema?

Use hasCertification on the Product block with a Certification object. Set name to the authentication certificate type ('Entrupy Authentication Certificate', 'Real Authentication Certificate', 'GOAT Verified'). Set issuedBy to the authenticating organization. Include certificationIdentification with the certificate ID or serial number so buyers can look up the authentication record. Also add an additionalProperty with propertyID 'serialNumber' and the item's serial number or reference number — this is the machine-readable provenance signal AI agents use when answering 'authenticated used Chanel bag serial number' queries. For watches, add propertyID 'caseReference' with the manufacturer case reference number.

Q: Should I set originalRetailPrice for pre-owned products?

Yes — for pre-owned luxury and high-value goods, adding a ListPrice PriceSpecification on the Offer is valuable. Set priceType to 'https://schema.org/ListPrice' with the original retail price. This gives AI agents the context to answer 'how much does a used Rolex Submariner cost compared to new' and to signal the discount magnitude. Use priceType: 'https://schema.org/SalePrice' for the actual asking price and 'https://schema.org/ListPrice' for the original retail comparator. Do NOT use compare_at_price semantics here — that signals a sale price reduction, not a new-vs-pre-owned comparison.

Q: How do I handle serialNumber and provenance in product schema?

Use the identifier property on the Product block with a PropertyValue object: { '@type': 'PropertyValue', 'propertyID': 'serialNumber', 'name': 'Serial Number', 'value': 'XYZ12345' }. You can also use the top-level serialNumber property directly on Product. For vintage or collectible items with multiple provenance identifiers (catalog number, edition number, lot number), use multiple additionalProperty entries with consistent propertyIDs. For watches: caseReference and serialNumber. For sneakers: StyleCode and colorway. For electronics: IMEI, serial number. Provenance signals are critical for AI queries like 'pre-owned iPhone 14 Pro with serial number' and 'authenticate vintage Rolex'.

Q: How do refurbished electronics differ from used products in schema?

Set itemCondition to 'https://schema.org/RefurbishedCondition' instead of UsedCondition. Add additionalProperty entries for refurbishmentLevel ('Manufacturer Refurbished', 'Seller Refurbished', 'Certified Pre-Owned'), refurbishingLab (the organization that performed the refurbishment), and warrantyIncluded ('90-day warranty', '1-year warranty'). For CPO (Certified Pre-Owned) programs, use hasCertification with the CPO program name and the certifying manufacturer as issuedBy. Apple Certified Refurbished, Dell Renewed, and similar OEM CPO programs significantly increase AI agent confidence in refurbished product listings.

The pre-owned and resale market on Shopify has exploded — luxury resale, certified pre-owned electronics, vintage clothing, and refurbished gear are now major Shopify store categories. AI shopping agents specifically filter for condition, authentication status, and original retail price comparison. Without machine-readable condition signals, every pre-owned listing looks identical to a new product from the agent's perspective.

TL;DR Set itemCondition on the Offer object using the schema.org enum URLs (UsedCondition, RefurbishedCondition, etc.); add additionalProperty with conditionGrade string for sub-classification (Like New, Excellent, Very Good, Good); use hasCertification for authentication certificates; add serialNumber or identifier for provenance; and use ListPrice PriceSpecification for original retail comparison.

itemCondition: The Primary Condition Signal

The itemCondition property belongs on the Offer object, not on the Product root. It takes a schema.org enum URL as its value. These are the five defined values:

Schema.org URL	Short name	Use for	AI queries matched
`https://schema.org/NewCondition`	New	Brand new, never used, original packaging	"buy new [product]"
`https://schema.org/UsedCondition`	Used	Pre-owned, secondhand, previously used	"used [product]", "pre-owned [product]", "secondhand [product]"
`https://schema.org/RefurbishedCondition`	Refurbished	Professionally restored, tested, certified	"refurbished [product]", "certified pre-owned [product]"
`https://schema.org/DamagedCondition`	Damaged	As-is, known defects, sold for parts/repair	"damaged [product] for parts", "as-is [product]"
`https://schema.org/OldCondition`	Old	Vintage, antique, collectible age designation	"vintage [product]", "antique [product]"

Condition only in title (not machine-readable)

{
  "@type": "Product",
  "name": "USED - Louis Vuitton Neverfull MM",
  "offers": {
    "@type": "Offer",
    "price": "890.00"
    // No itemCondition
    // AI: cannot filter by condition
    // Looks identical to new listing
  }
}

itemCondition on Offer (machine-readable)

{
  "@type": "Product",
  "name": "Louis Vuitton Neverfull MM Monogram",
  "offers": {
    "@type": "Offer",
    "price": "890.00",
    "itemCondition":
      "https://schema.org/UsedCondition"
  }
  // AI: condition filter → used match
}

Condition Grades: additionalProperty Sub-Classification

The five schema.org condition enum values are too coarse for resale — "Used" covers everything from Like New to Fair. AI agents use additionalProperty condition grade strings to match condition-qualified queries like "pre-owned MacBook excellent condition" or "used Lululemon very good".

Use consistent grade vocabulary across your catalog. The Mercari/eBay/The Real Real grading systems are the most widely recognized — AI agents are trained on data from these platforms and match against their terminology.

conditionGrade value	Description	itemCondition pairing	Platform equivalents
`Like New`	Worn/used once or twice; pristine condition with all original packaging	UsedCondition	eBay: Like New; Poshmark: NWT/NWOT; The RealReal: Excellent+
`Excellent`	Light use; no visible flaws; no missing parts	UsedCondition	eBay: Very Good; The RealReal: Excellent; Vestiaire: Very Good
`Very Good`	Normal use; minor cosmetic wear only; fully functional	UsedCondition	eBay: Good; ThredUp: Good; Mercari: Good
`Good`	Visible wear commensurate with age; fully functional	UsedCondition	eBay: Acceptable; Depop: Used; Back Market: Good
`Fair`	Significant wear or cosmetic flaws; functional	UsedCondition	Back Market: Fair; Swappa: Good (with noted flaws)
`For Parts / Repair`	Non-functional or major damage; sold for parts	DamagedCondition	eBay: For parts or not working; Swappa: For Parts
`Manufacturer Refurbished`	Refurbished by OEM; may include OEM warranty	RefurbishedCondition	Apple Certified Refurbished; Dell Renewed
`Seller Refurbished`	Refurbished by independent reseller; tested and cleaned	RefurbishedCondition	Back Market: Good/Excellent; Amazon Renewed

Complete JSON-LD Example: Authenticated Pre-Owned Luxury Bag

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": "Louis Vuitton Neverfull MM — Damier Azur — Pre-Owned Excellent",
  "description": "Pre-owned Louis Vuitton Neverfull MM in Damier Azur canvas. Condition: Excellent — light use, clean interior, no pen marks, hardware with minimal scratching. Authenticated by Entrupy with certificate ID ENT-2025-882014. Serial number MI1016 (manufactured October 2016, Asnieres France).",
  "url": "https://example.com/products/lv-neverfull-mm-azur-mi1016",
  "sku": "RESALE-LV-NF-AZ-001",
  "brand": { "@type": "Brand", "name": "Louis Vuitton" },
  "serialNumber": "MI1016",
  "identifier": [
    {
      "@type": "PropertyValue",
      "propertyID": "serialNumber",
      "name": "LV Date Code",
      "value": "MI1016"
    }
  ],
  "image": [
    "https://example.com/cdn/shop/products/lv-neverfull-front.jpg",
    "https://example.com/cdn/shop/products/lv-neverfull-interior.jpg",
    "https://example.com/cdn/shop/products/lv-neverfull-hardware.jpg",
    "https://example.com/cdn/shop/products/lv-neverfull-auth-cert.jpg"
  ],
  "offers": {
    "@type": "Offer",
    "price": "895.00",
    "priceCurrency": "USD",
    "itemCondition": "https://schema.org/UsedCondition",
    "availability": "https://schema.org/InStock",
    "url": "https://example.com/products/lv-neverfull-mm-azur-mi1016",
    "priceSpecification": [
      {
        "@type": "PriceSpecification",
        "price": "895.00",
        "priceCurrency": "USD",
        "priceType": "https://schema.org/SalePrice"
      },
      {
        "@type": "PriceSpecification",
        "price": "1570.00",
        "priceCurrency": "USD",
        "priceType": "https://schema.org/ListPrice",
        "description": "Original retail price (Louis Vuitton, 2024)"
      }
    ]
  },
  "hasCertification": [
    {
      "@type": "Certification",
      "name": "Entrupy Authentication Certificate",
      "certificationIdentification": "ENT-2025-882014",
      "issuedBy": {
        "@type": "Organization",
        "name": "Entrupy Inc.",
        "url": "https://www.entrupy.com"
      },
      "certificationStatus": "CertificationActive"
    }
  ],
  "additionalProperty": [
    {
      "@type": "PropertyValue",
      "propertyID": "conditionGrade",
      "name": "Condition Grade",
      "value": "Excellent"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "conditionNotes",
      "name": "Condition Notes",
      "value": "Light use. Clean interior, no pen marks or stains. Vachetta leather lightly honey-patinated. Zip pull hardware with minimal surface scratching. All hardware functions correctly."
    },
    {
      "@type": "PropertyValue",
      "propertyID": "serialNumber",
      "name": "Date Code",
      "value": "MI1016"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "manufactureDate",
      "name": "Manufacture Date",
      "value": "October 2016"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "manufactureLocation",
      "name": "Made In",
      "value": "France (Asnieres workshop)"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "authenticated",
      "name": "Authentication",
      "value": "Entrupy certified authentic — certificate ENT-2025-882014"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "includes",
      "name": "Included Items",
      "value": "Dust bag, padlock and keys, authenticity certificate"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "originalRetailPrice",
      "name": "Original Retail Price",
      "value": "$1,570 USD (Louis Vuitton, 2024)"
    }
  ]
}
</script>

Refurbished Electronics: Complete Example

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": "Apple MacBook Pro 14-inch M3 Pro — Refurbished Excellent — 18GB/512GB",
  "description": "Professionally refurbished MacBook Pro 14-inch M3 Pro. Grade: Excellent — fully functional, battery health 94%, cosmetically clean with no visible scratches. Includes 90-day warranty. Third-party tested by Aztek Electronics.",
  "url": "https://example.com/products/mbp14-m3pro-refurb-excellent",
  "sku": "REFURB-MBP14-M3P-512-001",
  "brand": { "@type": "Brand", "name": "Apple" },
  "model": "MacBook Pro 14-inch M3 Pro",
  "offers": {
    "@type": "Offer",
    "price": "1649.00",
    "priceCurrency": "USD",
    "itemCondition": "https://schema.org/RefurbishedCondition",
    "availability": "https://schema.org/InStock",
    "url": "https://example.com/products/mbp14-m3pro-refurb-excellent",
    "warranty": {
      "@type": "WarrantyPromise",
      "durationOfWarranty": {
        "@type": "QuantitativeValue",
        "value": 90,
        "unitCode": "DAY"
      },
      "warrantyScope": "Parts and labor; covers functional defects"
    },
    "priceSpecification": [
      {
        "@type": "PriceSpecification",
        "price": "1649.00",
        "priceCurrency": "USD",
        "priceType": "https://schema.org/SalePrice"
      },
      {
        "@type": "PriceSpecification",
        "price": "1999.00",
        "priceCurrency": "USD",
        "priceType": "https://schema.org/ListPrice",
        "description": "New retail price (Apple.com)"
      }
    ]
  },
  "additionalProperty": [
    {
      "@type": "PropertyValue",
      "propertyID": "conditionGrade",
      "name": "Condition Grade",
      "value": "Seller Refurbished — Excellent"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "batteryHealth",
      "name": "Battery Health",
      "value": "94%"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "refurbishmentLevel",
      "name": "Refurbishment Level",
      "value": "Seller Refurbished"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "testingLab",
      "name": "Tested By",
      "value": "Aztek Electronics (CTIA-certified refurbisher)"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "warrantyIncluded",
      "name": "Warranty",
      "value": "90-day parts and labor warranty"
    },
    {
      "@type": "PropertyValue",
      "propertyID": "includes",
      "name": "Box Contents",
      "value": "MacBook Pro, USB-C charging cable, 96W power adapter"
    }
  ]
}
</script>

Authentication Certifications for Luxury Resale

Authentication service	Specialization	AI queries matched
Entrupy	Luxury handbags, sneakers, apparel (AI-powered)	"Entrupy authenticated Louis Vuitton", "authenticated pre-owned Gucci"
Real Authentication	Luxury handbags, accessories, watches	"Real Authentication certificate handbag"
Legit Check By Ch	Sneakers, streetwear	"authenticated Jordan 1 resale", "legit checked sneakers"
WatchCSA	Luxury watches	"authenticated pre-owned Rolex", "certified used Omega watch"
GIA (Gemological Institute)	Diamonds, gemstones, fine jewelry	"GIA certified diamond ring", "GIA graded pre-owned engagement ring"
PSA (Professional Sports Authenticator)	Sports cards, memorabilia	"PSA graded baseball card", "PSA 9 rookie card"
CGC (Certified Guaranty Company)	Comics, magazines, books	"CGC graded comic book", "CGC 9.8 first appearance"

Shopify Liquid Snippet for Resale Condition Schema

{% comment %} resale-schema.liquid — condition and authentication JSON-LD {% endcomment %}
{% assign cond_grade   = product.metafields.resale.condition_grade %}
{% assign cond_notes   = product.metafields.resale.condition_notes %}
{% assign serial_num   = product.metafields.resale.serial_number %}
{% assign orig_price   = product.metafields.resale.original_retail_price %}
{% assign auth_json    = product.metafields.resale.authentication %}
{% assign cond_enum    = product.metafields.resale.condition_enum | default: 'UsedCondition' %}

{% if cond_grade != blank %}

{% endif %}

Common Pre-Owned Schema Mistakes

#	Mistake	Impact	Fix
1	No `itemCondition` — condition only in product title ("USED -")	AI agents cannot distinguish new vs. used listings; pre-owned products appear alongside new in condition-filtered queries	Set `itemCondition` on the `Offer` object using the full schema.org enum URL
2	`itemCondition` set on Product root instead of Offer	Schema.org specifies `itemCondition` is a property of `Offer`, not `Product` — placing it on the wrong object means some parsers ignore it	Move `itemCondition` inside the `offers` object block
3	Authentication certificate only in product description text	AI cannot verify authentication status from text alone; `hasCertification` is the explicit machine-readable signal	Add `hasCertification` with the authentication service name and certificate ID for every authenticated item
4	No serial number or provenance identifiers	Pre-owned luxury and electronics queries often include serial number lookups; missing identifiers reduce AI agent confidence in listing legitimacy	Add `serialNumber` property and/or `identifier` PropertyValue blocks for every item with a traceable provenance identifier
5	No original retail price comparison	AI agents answering "how much is a used [item] compared to new?" cannot surface the comparison without a `ListPrice` PriceSpecification	Add original retail price as a `ListPrice` PriceSpecification in `priceSpecification` array on the Offer

Frequently Asked Questions

What are the itemCondition values for used and refurbished products?

Schema.org defines five itemCondition enum values, all set on the Offer object: NewCondition, UsedCondition, RefurbishedCondition, DamagedCondition, and OldCondition. For sub-classification, pair with additionalProperty using propertyID: "conditionGrade" and values like "Like New", "Excellent", "Very Good", "Good", "Fair". AI agents use both the enum (for binary condition filtering) and the grade string (for nuanced condition queries).

How do I express a luxury authentication certificate in schema?

Use hasCertification on the Product block with a Certification object. Set name to the authentication certificate type (e.g., "Entrupy Authentication Certificate"), issuedBy to the authenticating organization, and certificationIdentification to the certificate ID. Also add the item's serial number or date code in serialNumber and as an additionalProperty entry with propertyID: "serialNumber".

Should I set originalRetailPrice for pre-owned products?

Yes — for pre-owned luxury and high-value goods, add a ListPrice PriceSpecification in the priceSpecification array on the Offer. This enables AI agents to answer "how much is a used [item] compared to new?" and signals the discount magnitude. Use priceType: "https://schema.org/ListPrice" for the original retail value and priceType: "https://schema.org/SalePrice" for your asking price.

How do I handle serialNumber and provenance in product schema?

Use the top-level serialNumber property directly on Product, and add a parallel identifier PropertyValue or additionalProperty entry with propertyID: "serialNumber" for AI agents that scan additionalProperty arrays. For watches, add caseReference. For sneakers, add styleCode. For electronics, add IMEI. Multiple provenance identifiers are supported via multiple additionalProperty entries.

How do refurbished electronics differ from used products in schema?

Set itemCondition to https://schema.org/RefurbishedCondition instead of UsedCondition. Add additionalProperty entries for refurbishmentLevel ("Manufacturer Refurbished" vs. "Seller Refurbished"), testingLab, and warrantyIncluded. For OEM CPO programs (Apple Certified Refurbished, Dell Renewed), add hasCertification with the CPO program name and the manufacturer as issuedBy. A WarrantyPromise on the Offer further boosts refurbished listing confidence for AI agents.