Metafields & Metaobjects — Adding Custom Data Without Any App

Need to display ingredient lists, care instructions, a size guide that's different for each product, or per-product FAQ sections? Shopify has had a built-in solution since 2021 — no app, no extra cost, no impact on your store's speed. Most merchants just don't know it exists.

What is a Metafield and when do you need one?

A Metafield is a custom data field you define and attach to a product, collection, page, order, or customer. Shopify's default structure only includes fixed fields: title, description, price, images, vendor. When your products need additional specific information — technical specifications, care instructions, ingredients, warnings, document downloads — metafields are the right tool.

The most important thing to understand about metafields: they're structured data, not just extra text stuck into a description field. This means different types of content get appropriate formatting, values can be validated, and the data can be connected to your theme dynamically — so the same layout displays the right content for each individual product automatically.

Common use cases where metafields shine: ingredient lists for cosmetics or food products, care and washing instructions for fashion, technical specifications for electronics, certifications and awards, per-product FAQ content, downloadable files like PDF manuals or assembly guides, and cross-references to related content like a size guide shared across multiple products.

Creating a metafield definition in Admin

Go to Settings → Custom data → Products (or Collections / Pages / Customers / Orders depending on what you're attaching data to). Click "Add definition."

The three fields that matter:

• Name — The display name in Admin. Keep it clear and human-readable: "Care Instructions," "Ingredients," "Technical Specs"
• Namespace & Key — The technical identifier used to reference this metafield in Liquid code and Dynamic Sources. Shopify auto-generates one, which you can keep: custom.care_instructions. The namespace groups related metafields; the key identifies the specific one
• Content type — The data format: Single-line text, Multi-line text, Number (integer or decimal), Date/time, True/false (checkbox), File (PDF, image), URL, Reference (to another product, collection, or metaobject), Color, Weight, Dimension, Volume — the right type ensures correct validation and display

Once you've created the definition, go to any product and scroll to the very bottom — a new "Metafields" section appears where you can enter the content for that specific product. Each product can have different content in the same metafield.

Displaying metafields in Theme Editor with Dynamic Sources

Creating a metafield definition and filling in content is only half the job — the content also needs to appear somewhere on the product page for customers to see. This is where Dynamic Sources come in (covered in NC-01).

In Theme Editor: select a text block on the product template → click the ⚡ lightning bolt icon next to the content field → choose your metafield from the dropdown. That block will then automatically display the correct metafield content for whatever product is being viewed — no manual linking needed per product.

💡 Dynamic Sources in Theme Editor only work with OS 2.0 themes. If your theme is an older architecture, you'll need to call the metafield directly in Liquid code within a section file: {{ product.metafields.custom.ingredients }}. The metafield data is the same — only the display method differs.

Metaobjects — custom data types you define entirely

If metafields attach data to existing Shopify objects (products, collections, etc.), Metaobjects are completely custom data structures you create from scratch — with multiple fields inside, instances you create and manage, and the ability to be referenced from multiple products or pages.

The size guide example shows why Metaobjects are powerful: rather than duplicating the same size chart content across 50 product descriptions, you create one Size Guide Metaobject entry and have all relevant products reference it. When the size chart needs updating (different season, new fit), you edit the Metaobject once and every product updates instantly.

Other strong Metaobject use cases: brand or author profiles, store location data, FAQ collections reused across pages, team member bios, ingredient specifications used across product categories. Go to Settings → Custom data → Metaobjects → Add definition to create the structure, then Content → Metaobjects to create actual entries.

Which apps can metafields replace?

The speed and cost savings from replacing apps with metafields are real and measurable. Every app removed is one less JavaScript file loading on every page, one less monthly charge, and one less potential source of theme conflicts. Metafields load with the page data directly — zero additional JavaScript, zero additional requests.