Adding Custom Data to Products and Collections | Help Center

Custom Fields for Products, Collections, and More

Custom Data lets you store extra information on your products, collections, orders, and customers beyond Cartly's built-in fields. For example, you could add a "Material" field to every product or a "Lead Time" field to collections.

What Are Metafields?

Metafields are key-value pairs attached to a Cartly entity. A product could have a metafield in the custom namespace with the key material and the value 100% cotton. You decide the structure; Cartly stores and validates the data.

Setting Up a Field Definition

Navigate to Settings → Custom Data and select the entity type (Products, Collections, Orders, or Customers). Click Add Definition and fill in:

Name — Human-readable label shown in the admin (e.g., "Material")
Namespace — A grouping prefix, usually custom for your own fields
Key — The field identifier used in Liquid and the API (e.g., material)
Type — The data type: text, number, boolean, date, color, URL, file, or a reference to another product/collection/metaobject

Once a definition exists, Cartly validates every value written to that field. For example, a number_integer field will reject a text value.

Editing Metafield Values

After defining fields, they appear at the bottom of every product (or collection, order, customer) edit page. Simply fill them in and save as normal.

Using Metafields in Your Theme

Metafields are available in Liquid templates as {{ product.metafields.custom.material }}. Install a theme that references custom fields, or add the output to your Liquid sections manually.

What Are Metaobjects?

Metaobjects are custom content types — like a mini CMS for structured records. Navigate to Content → Custom Content to create a definition (e.g., "Designer Profile") with multiple typed fields, then add entries (e.g., one entry per designer). You can link products to designer entries via a metaobject_reference metafield.

Metaobject Use Cases

Designer or brand profiles linked to products
Size guide tables with columns and rows
FAQ entries displayed on product pages
Testimonials or team member profiles

API and GraphQL Access

Metafields and metaobjects are accessible via the Cartly REST API and GraphQL Storefront API, making them available to custom storefronts and third-party apps.