Product Identifier [item_id] for Product Feeds

Required product identifier for ChatGPT

The item_id field is the primary product identifier used by ChatGPT to uniquely reference each product or variant.

It acts as the stable key that allows ChatGPT to:

• track products over time,
• associate updates (price, availability),
• group variants correctly,
• avoid duplication.

This field replaces the legacy id attribute.
The old name is no longer supported.

When to use

Use item_id for every product and every variant in your feed.

Each value must:

• uniquely identify a single product variant,
• remain stable over time,
• never be reused for a different product.

Changing item_id values resets the product identity in ChatGPT.

Format

• Type: String (alphanumeric)
• Maximum length: 100 characters
• Repeated field: No
• Case sensitivity: Case-sensitive

Examples:

Accepted characters typically include letters, numbers, hyphens, underscores, and dots.

Relationship with variants

When products have variants:

• each variant must have its own unique item_id,
• variants are grouped together using group_id.

Never reuse the same item_id across multiple variants.

Minimum requirements

• Provide a unique value per product variant.
• Keep the value stable over time.
• Ensure item_id is never empty.
• Do not reuse identifiers for different products.
• Do not change identifiers unnecessarily.

SEO / AI Tip

ChatGPT relies heavily on item_id to reconcile feed updates.
Inconsistent or changing identifiers can result in:

• duplicate products,
• lost history,
• unstable visibility.

Treat item_id as a permanent product key, not a temporary label.

Official Source:
ChatGPT Product Feed Specs