shopify-developer

What this skill does

# Shopify Developer Reference

Comprehensive reference for professional Shopify development - API version **2026-01**.

## Quick Reference

| Item | Value |
|------|-------|
| API version | `2026-01` (stable) |
| GraphQL Admin | `POST https://{store}.myshopify.com/admin/api/2026-01/graphql.json` |
| Storefront API | `POST https://{store}.myshopify.com/api/2026-01/graphql.json` |
| Ajax API (theme) | `/cart.js`, `/cart/add.js`, `/cart/change.js` |
| CLI install | `npm install -g @shopify/cli` |
| Theme dev | `shopify theme dev --store {store}.myshopify.com` |
| App dev | `shopify app dev` |
| Deploy | `shopify app deploy` |
| Docs | [shopify.dev](https://shopify.dev) |

## Choose Your Path

Read the reference file(s) that match your task:

**Liquid templating** - writing or debugging `.liquid` files:

- [references/liquid-syntax.md](references/liquid-syntax.md) - Tags, control flow, iteration, whitespace, LiquidDoc
- [references/liquid-filters.md](references/liquid-filters.md) - All filter categories with examples
- [references/liquid-objects.md](references/liquid-objects.md) - Product, collection, cart, customer, and global objects

**Theme development** - building or customising themes:

- [references/theme-development.md](references/theme-development.md) - OS 2.0 architecture, sections, blocks, JSON templates, settings schema

**API integration** - fetching or modifying data programmatically:

- [references/api-admin.md](references/api-admin.md) - GraphQL Admin API (primary), REST (legacy), OAuth, webhooks, rate limiting
- [references/api-storefront.md](references/api-storefront.md) - Storefront API, Ajax API, cart operations

**App development** - building Shopify apps:

- [references/app-development.md](references/app-development.md) - Shopify CLI, extensions, Polaris Web Components, App Bridge

**Serverless logic** - custom business rules:

- [references/functions.md](references/functions.md) - Shopify Functions (replacing Scripts), Rust/JS targets, deployment

**Headless commerce** - custom storefronts:

- [references/hydrogen.md](references/hydrogen.md) - Hydrogen framework, React Router 7, Storefront API integration

**Optimisation and troubleshooting**:

- [references/performance.md](references/performance.md) - Images, JS, CSS, fonts, Liquid, Core Web Vitals
- [references/debugging.md](references/debugging.md) - Liquid errors, API errors, cart issues, webhook failures

## Deprecation Notices

| Deprecated | Replacement | Deadline |
|------------|-------------|----------|
| Shopify Scripts | Shopify Functions | August 2025 (migration), sundown TBD |
| checkout.liquid | Checkout Extensibility | August 2024 (Plus), done |
| REST Admin API | GraphQL Admin API | Active deprecation (no removal date yet) |
| Legacy custom apps | New auth model | January 2025 (done) |
| Polaris React | Polaris Web Components | Active migration |
| Remix (app framework) | React Router 7 | Hydrogen 2025.5.0+ |

## Liquid Essentials

Three syntax types:

```liquid
{{ product.title | upcase }}                    {# Output with filter #}
{% if product.available %}In stock{% endif %}   {# Logic tag #}
{% assign sale = product.price | times: 0.8 %}  {# Assignment #}
{%- if condition -%}Stripped whitespace{%- endif -%}
```

Key patterns:

```liquid
{% for product in collection.products limit: 5 %}
  {% render 'product-card', product: product %}
{% endfor %}

{% paginate collection.products by 12 %}
  {% for product in paginate.collection.products %}...{% endfor %}
  {{ paginate | default_pagination }}
{% endpaginate %}
```

## API Essentials

```javascript
// GraphQL Admin - always use GraphQL over REST
const response = await fetch(
  `https://${store}.myshopify.com/admin/api/2026-01/graphql.json`,
  {
    method: 'POST',
    headers: {
      'X-Shopify-Access-Token': accessToken,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ query, variables }),
  }
);
const { data, errors } = await response.json();
if (errors) throw new Error(errors[0].message);

// Ajax API (theme-only cart operations)
fetch('/cart/add.js', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ id: variantId, quantity: 1 }),
});
```

## Reference Files

| File | Lines | Coverage |
|------|-------|----------|
| [liquid-syntax.md](references/liquid-syntax.md) | ~600 | Tags, control flow, iteration, variables, whitespace, LiquidDoc |
| [liquid-filters.md](references/liquid-filters.md) | ~870 | String, numeric, array, Shopify-specific, date, URL, colour filters |
| [liquid-objects.md](references/liquid-objects.md) | ~695 | All Shopify objects: product, variant, collection, cart, customer, order, etc. |
| [theme-development.md](references/theme-development.md) | ~1200 | File structure, JSON templates, sections, blocks, settings schema, layout |
| [api-admin.md](references/api-admin.md) | ~595 | GraphQL queries/mutations, REST (legacy), OAuth, webhooks, rate limiting |
| [api-storefront.md](references/api-storefront.md) | ~235 | Storefront API, Ajax API, cart operations, Customer Account API |
| [app-development.md](references/app-development.md) | ~760 | CLI, app architecture, extensions, Polaris Web Components, deployment |
| [functions.md](references/functions.md) | ~300 | Function types, Rust/JS targets, CLI workflow, Scripts migration |
| [hydrogen.md](references/hydrogen.md) | ~375 | Setup, routing, data loading, Storefront API, deployment |
| [performance.md](references/performance.md) | ~605 | Images, JS, CSS, fonts, Liquid, third-party scripts, Core Web Vitals |
| [debugging.md](references/debugging.md) | ~650 | Liquid, JavaScript, API, cart, webhook, theme editor troubleshooting |