shopify-developer

# 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-storefron