shopify-metafields-metaobjects

Shopify Metafields & Metaobjects

Overview

Metafields attach key-value custom data to existing resources (products, variants, orders, customers). Metaobjects define entirely new content types with custom schemas. Together they replace the need for external databases for most custom data needs.

Prerequisites

• Completed shopify-install-auth setup
• Access scopes: read_metaobjects, write_metaobjects, read_metaobject_definitions, write_metaobject_definitions
• Metafield scopes per resource: read_products/write_products for product metafields, etc.

Instructions

Step 1: Define a Metafield on Products

Use metafieldDefinitionCreate with namespace, key, type, and ownerType:

await client.request(METAFIELD_DEFINITION_CREATE, {
  variables: {
    definition: {
      namespace: "custom",
      key: "care_instructions",
      name: "Care Instructions",
      type: "multi_line_text_field",  // See references/metafield-types.md
      ownerType: "PRODUCT",
      pin: true, // Show in admin UI
    },
  },
});
// Always check userErrors — Shopify returns 200 even on validation failures

Step 2: Set Values in Batch with metafieldsSet

await client.request(METAFIELDS_SET, {
  variables: {
    metafields: [
      {
        ownerId: "gid://shopify/Product/123456",
        namespace: "custom",
        key: "care_instructions",
        value: "Machine wash cold.\nTumble dry low.",
        type: "multi_line_text_field",
      },
      // Up to 25 metafields per call
    ],
  },
});

Step 3: Create a Metaobject Definition

Define a custom content type (e.g., "Designer" with typed fields):

await client.request(METAOBJECT_DEFINITION_CREATE, {
  variables: {
    definition: {
      type: "$app:designer",
      displayNameKey: "name",
      fieldDefinitions: [
        { key: "name", name: "Name", type: "single_line_text_field" },
        { key: "bio", name: "Bio", type: "multi_line_text_field" },
        { key: "photo", name: "Photo", type: "file_reference" },
      ],
      access: { storefront: "PUBLIC_READ" },
    },
  },
});

Step 4: Create Metaobject Instances

await client.request(METAOBJECT_CREATE, {
  variables: {
    metaobject: {
      type: "$app:designer",
      handle: "jane-doe",
      fields: [
        { key: "name", value: "Jane Doe" },
        { key: "bio", value: "Award-winning textile designer." },
      ],
    },
  },
});

See metafield-types.md for all types, toml-config.md for app config, and bulk-metafield-ops.md for bulk operations.

Output

• Metafield definitions registered on target resource types
• Metafield values set on individual resources (batch supported, max 25 per call)
• Custom metaobject types with typed field schemas
• Metaobject instances queryable via Storefront and Admin APIs

Error Handling

Error	Cause	Solution
TAKEN	Namespace + key already exists on this owner type	Use metafieldDefinitionUpdate or choose a different key
INVALID_TYPE	Type string not in Shopify's registry	Check metafield-types.md
INVALID_VALUE	Value doesn't match declared type	Cast value to correct format before setting
TOO_LONG	Value exceeds type limit (512KB for text types)	Truncate or switch to multi_line_text_field

Examples

Adding Care Instructions to All Products

Define a "care_instructions" metafield on the PRODUCT owner type, then bulk-set values across hundreds of products in batches of 25.

See Bulk Metafield Ops for the batch set/delete operations.

Choosing the Right Metafield Type

You need to store a color swatch, a date range, or a product reference. Pick the correct type from Shopify's type registry.

See Metafield Types for the complete type list with value format examples.

Declaring Metafields in App Configuration

Define metafield and metaobject schemas in shopify.app.toml so they deploy automatically with the app instead of making API calls.

See TOML Config for the app configuration syntax.

Resources

• Metafield Definition API
• metafieldsSet Mutation
• Metaobject API Guide
• Metafield Types Reference