Color Attribute in Product Feeds: Format Rules and Variant Grouping

The color attribute looks simple until a disapproval lands in Merchant Center. A wrong separator, a generic placeholder or a mismatched landing-page value can pull a product offline. This article covers the precise formatting rules Google requires, the prohibited values that catch merchants off guard, and how color connects to variant grouping via item_group_id—going beyond the familiar apparel context.

Exact Format Rules for the Color Attribute

Google accepts color as a string of Unicode characters, with ASCII recommended. The hard limits are 1–100 characters total, and 1–40 characters per individual color Google documentation. Those are two separate constraints: a single color name must stay within 40 characters, and the combined value for a multi-color product must stay within 100 characters.

Multi-color syntax

When a product features more than one color, you may list a primary color followed by up to two secondary colors. The required separator is a forward slash (/). So a primary red with green and black accents is submitted as Red/Green/Black.

The following formats are all disapproved:

• Comma-separated: Red, Green, Black — Google documentation states "Don't submit multiple colors with a comma"; if you use commas, only one color will be applied.
• Concatenated: RedGreenBlack — treating combined colors as a single word is not accepted.
• Hex codes or non-alphanumeric characters: #fff000 is explicitly prohibited.
• Single letters: R is not accepted; you need more than one letter (exception: single CJK characters such as 红 are allowed).
• Numbers used as colors: 0 2 4 6 8 is prohibited.

Prohibited generic terms

The specification also explicitly disallows values that are not genuine color names. Terms such as variety, mens, womens, N/A, see image or any reference back to the product image are all rejected. These are treated as non-color values, not as color descriptions.

One attribute per variant

You submit one color attribute per product entry. If you provide multiple separate color attributes for the same variant, only the first is used and the rest are discarded with a warning. Multi-color products belong in a single attribute using the slash syntax described above.

Branded Color Names and Landing-Page Matching

A common source of mismatches is submitting a normalized color when the landing page uses a branded name—or vice versa.

The requirement is to use the same color in your product data as on your landing page. If your landing page says "Toasted Walnut", submitting "Brown" will create a data mismatch and can trigger a disapproval.

Branded names are explicitly supported. According to Google documentation, "If you describe your product on your landing page using a unique color, like 'Pop Girl' or 'High Five', submit that value through the color attribute." The recommended practice is then to pair that branded value in color with a plain searchable color name—such as "Red" or "Black"—in the product title, since customers are more likely to search for the standard name.

This two-layer approach keeps your feed compliant (the color attribute matches the landing page) while keeping your title discoverable (the title uses a term shoppers actually type).

How Color Connects to Variant Grouping

Color is not just a descriptive field—it directly drives how Google understands and displays your product variants. When a product exists in multiple color options, each color must be submitted as a separate product entry, and all those entries must share the same value for item_group_id.

The item_group_id attribute accepts alphanumeric characters, underscores and dashes, with a limit of 1–50 characters Google documentation. Casing is not a reliable differentiator: abc123 and ABC123 are treated as the same group, so do not rely on case alone to create distinct groups.

Variant grouping is not limited to apparel. The item_group_id documentation lists electronics variants—memory sizes, display sizes, processors and graphics options—as explicit examples. Color can be the differentiating attribute for any product category where variants differ by color: sunglasses, phone cases, water bottles, home accessories and so on.

Each variant's landing page URL should reflect the specific variant—for example /product/sunglasses?color=red—so that grouping in the feed matches the shopping experience on the site Google documentation.

As of May 2026: variant_option attribute

Google added a variant_option attribute that lets you explicitly identify the variant-identifying properties of a product. If color is one of those properties, Google recommends providing it in both variant_option and the standard color attribute. Providing both helps Google's systems understand your variants more accurately. This is a recommendation, not a current requirement to replace color.

Hypothetical Example: Home Goods Catalog

The following is a hypothetical example to illustrate formatting rules.

A home goods merchant sells a ceramic mug in three colorways: a solid navy, a clay tone with a cream interior, and a forest green with a matte black handle. Each colorway is a separate SKU.

Note that clay/cream stays well within the 40-character-per-color and 100-character-total limits. forest green/black uses the slash separator for a two-color entry—no commas, no hex codes. All three variants share the same item_group_id so Google can group them together.

A value like multi or see image in the color column, or forest-green,black using a comma, would cause a format error or disapproval.

Practical Audit Checklist

Before submitting or updating color values in your feed, check each of the following:

• Character count: Each color name is ≤ 40 characters; the combined value is ≤ 100 characters.
• Separator: Multiple colors use /, not , or a space.
• Landing-page match: The value submitted matches exactly what is shown on the product page.
• No generic placeholders: Values like N/A, variety or see image are removed.
• No hex codes or single letters: Only alphanumeric strings and Unicode color names.
• Variant grouping: Every color variant of the same product shares one item_group_id value.
• Unique IDs per variant: Each color variant has its own id.

Managing color values consistently across a large catalog—especially when product names come from a CMS or a Shopify metafield that uses branded names—is one of the more common sources of feed errors. Magicfeedpro is built to help you map, validate and maintain those values at scale so that color data stays consistent between your source catalog and your destination feeds.

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