What is a metafield? Shopify metafields explained

A metafield is a custom field that stores extra information on a Shopify product, collection, customer or order: a size chart, an ingredient list, care instructions, the notes of a scent. Shopify gives every product a title, price and description; metafields hold the rest, so one product page template can show the right facts for each product. Below: what a metafield is made of, the types you can pick, how to add one in 5 steps, and three product pages with hundreds of ads behind them that show these details well.

Takeaways: Define a metafield once in Settings, then fill in a value on each product. Pick the narrowest type that fits the detail (a number for calories, a list for scent notes) so the value stays clean. Connect it to your theme with a dynamic source and every product page shows its own details, with no code.

What is a metafield?

A metafield is a labeled slot for one piece of information that Shopify doesn't track by default. Shopify's own definition: metafields "extend an existing platform data model, such as products, customers, and orders with your own custom data" (Shopify Help Center).

Every metafield has three parts:

• Namespace and key: its address, written namespace.key, for example custom.care_instructions.
• Type: what kind of value it holds, such as text, a number, a date, a file or a link to another product.
• Value: the information itself, filled in per product, like "Machine wash cold and tumble dry low."

A product metafield is simply a metafield on a product; you can also add them to variants, collections, customers, orders, pages and blog posts. Before you fill in values, you create a metafield definition: the template that sets the name, type and rules. Shopify allows "up to 256 metafield definitions for each type, such as products or customers" (metafield definitions).

In your theme's code, the care instructions above read as product.metafields.custom.care_instructions. You rarely need to type that: Online Store 2.0 themes connect metafields to blocks in the theme editor.

What are metafields used for?

Anything a shopper needs to decide that doesn't fit in the title, price or description. Common examples by store type:

• Apparel: size chart, fit notes, inseam, fabric and care.
• Beauty and skincare: full ingredient list, skin type, key actives.
• Food and supplements: nutrition per serving, allergens, flavor notes.
• Home and furniture: dimensions, materials, assembly time, warranty.
• Electronics and parts: compatible models, battery life, specs.

Metafields on customers and orders mostly stay behind the scenes: a loyalty tier, a wholesale price list, a gift note for the packing team. Shopify Flow and apps can read and write them too.

Shopify metafield types

Pick the narrowest type that fits, because the type decides how the value is checked and shown (metafield types):

• Text: single line for short labels ("Made in Portugal"), multi-line for paragraphs, rich text for formatted copy.
• Numbers: integer or decimal, for calories, grams of protein or a capacity.
• Measurements: dimension, weight and volume, with units Shopify formats for you.
• True or false: for flags like "vegan" or "ships in 24 hours".
• Dates: a launch date or a best-before date.
• Files: an image, PDF or video, such as a sizing guide or manual.
• References: a link to another product, variant, collection, page or metaobject.
• Money, rating, color, URL and JSON: for the jobs their names describe.

Most types also come as a list, which holds several values in one field: three scent notes, five compatible models, a set of related products.

Category metafields are a special case. When you set a product's category, Shopify suggests attributes for it, such as color, size or fabric, which it calls product attributes (category metafields). Fill them in: they feed your store's filters and search.

How to add a metafield in Shopify

You can add a product metafield in Shopify admin in five steps. This example adds care instructions:

1. Open custom data. In Shopify admin, go to Settings, then Custom data, and choose Products.
2. Add a definition. Click Add definition and name it "Care instructions". Shopify fills in the namespace and key (custom.care_instructions).
3. Choose the type. Pick Multi-line text. Add validation if you need it, and turn on storefront access so your theme and apps can read it.
4. Fill in values. Save, open a product, scroll to the Metafields section and enter that product's care instructions. Repeat for each product, or use Shopify's bulk editor to fill in many at once.
5. Show it on the page. Go to Online Store, then Themes, then Customize. Open your product template, add a text or collapsible row block, and use the dynamic source button to connect it to Care instructions.

Every product page now shows its own care instructions in that block. Older themes that don't support dynamic sources need a line of Liquid in the product template, for example {{ product.metafields.custom.care_instructions.value }}, which Shopify documents in its Liquid reference.

3 product pages that show metafield-style details

These product pages each have dozens to hundreds of live Meta ads linked to them, and all three stores run on Shopify. We can't see inside their admin, but every block below is a per-product detail of the kind metafields hold: the same layout, different facts for each product.

Be Amazing: nutrition for each flavor

Be Amazing's vegan protein page has over 750 Meta ads linked to it. Next to the photo, a panel lists what's in each scoop: 20g protein, 140 calories, 1g or less sugar, 2g prebiotic fiber, plus a one-line flavor note. As number fields, those facts can change with each flavor while the panel stays in the same spot.

Drift: three notes for every scent

Drift's wood car freshener page has over 850 Meta ads linked to it. Every scent in the picker shows three notes with an icon each: Cabana is coconut, bergamot and cedarwood. That's a list field on each scent, so adding a new scent means filling in three notes, not designing a new card.

Alo: fit, fabric and care in one row

Alo's Suit Up trouser page has over 50 Meta ads linked to it. Under the photos, three columns answer the questions that stop an apparel sale: how it fits (size down, 28" inseam), what it's made of (86% polyester, 14% elastane) and how to wash it. Each column is one field per product.

Metafields vs metaobjects vs tags

• Metafield: one detail on one product, like its fabric. Use it for facts that differ per product.
• Metaobject: a reusable entry with its own fields, like a size chart or a designer profile. Make one size chart and point every product that uses it there through a metafield (metaobjects).
• Tag: a loose label for sorting, like "summer". Tags are fine for smart collections but can't hold a value or check its format, so move product details out of tags and into metafields.

Tips for clean metafields

• Use Shopify's standard definitions first. Shopify offers ready-made ones, such as product subtitle or care guide, that themes and apps already understand.
• Name for the shopper. "Care instructions" reads better in the admin and the theme editor than "ci_txt".
• One fact per field. Calories and protein as two numbers can be sorted, filtered and reused; one text blob can't.
• Don't change a type in place. Create a new definition, copy the values over, check the page, then delete the old one.
• Hide empty blocks. If some products have no value, make sure the theme block disappears instead of showing a blank heading.

Show your metafields on landing pages too

A size chart or nutrition panel shouldn't vanish when an ad sends shoppers to a landing page instead of the product page. Replo reads your Shopify products, collections, metafields and discounts, so a landing page built for one ad can show the same details as the product page, and every buy button goes to your Shopify cart and checkout. See how the Shopify integration works, or read our guide to Shopify product page customizations.

Start for free and build a landing page with your real product data.