Shopify Development

Shopify Development — questions and answers

What are metafields in Shopify and why do developers use them?

Metafields let you store custom data that Shopify's standard product, collection or order fields don't cover—things like fabric composition, care instructions, or supplier codes. Developers use them to extend Shopify's data model without altering its core structure, then surface that data in themes using Liquid or access it programmatically through APIs. They're defined with a namespace, key and value type.

How does Liquid templating differ from working in a standard programming language?

Liquid is a template language, not a general-purpose programming language, so it lacks features like arbitrary loops, complex conditionals or the ability to define functions. You output data and apply filters, but logic stays simple by design. This constraint keeps templates readable for non-developers but means complex operations need to happen server-side in an app or through API calls before rendering.

When does a Shopify store need a custom app rather than theme customisation?

Theme code runs when pages render and can only display or lightly manipulate data Shopify already has. If you need to process data on a schedule, respond to webhooks, store information outside Shopify's standard models, integrate deeply with external systems, or add functionality to the Shopify admin itself, you need an app. Apps run server-side and can use any programming language.

What's the practical difference between Shopify's Admin API and Storefront API?

The Admin API gives full read-write access to a store's data—products, orders, customers, inventory—and is used by apps that manage store operations or sync with other systems. The Storefront API is read-focused and designed for building custom buying experiences: it exposes products and collections but can't access sensitive admin data or modify store settings. Each has different authentication requirements and rate limits.

Why do Shopify theme sections exist, and what problems do they solve?

Sections are self-contained blocks of theme code that merchants can add, remove and rearrange through the theme editor without touching code. They solve the problem of rigid page layouts by making themes modular. Each section bundles its Liquid template, schema definition for settings, and optional CSS and JavaScript. Developers structure themes around sections to give merchants flexibility while maintaining design consistency.

What causes Shopify API rate limit errors, and how should apps handle them?

Shopify limits how many API requests an app can make per second using a leaky bucket algorithm—typically 2 requests per second for REST, with burst capacity. Apps hit limits when making too many requests too quickly, often during bulk operations. Proper handling means checking the rate limit headers in responses, implementing exponential backoff when throttled, and batching operations where possible using GraphQL or bulk APIs.