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

Choose Your Path

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

Liquid templating - writing or debugging .liquid files:

• references/liquid-syntax.md - Tags, control flow, iteration, whitespace, LiquidDoc

• references/liquid-filters.md - All filter categories with examples

• references/liquid-objects.md - Product, collection, cart, customer, and global objects

Theme development - building or customising themes:

• 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 - GraphQL Admin API (primary), REST (legacy), OAuth, webhooks, rate limiting

• references/api-storefront.md - Storefront API, Ajax API, cart operations

App development - building Shopify apps:

• references/app-development.md - Shopify CLI, extensions, Polaris Web Components, App Bridge

Serverless logic - custom business rules:

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

Headless commerce - custom storefronts:

• references/hydrogen.md - Hydrogen framework, React Router 7, Storefront API integration

Optimisation and troubleshooting:

• references/performance.md - Images, JS, CSS, fonts, Liquid, Core Web Vitals

• 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:

{{ 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:

{% 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

// 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 ~600 Tags, control flow, iteration, variables, whitespace, LiquidDoc

liquid-filters.md ~870 String, numeric, array, Shopify-specific, date, URL, colour filters

liquid-objects.md ~695 All Shopify objects: product, variant, collection, cart, customer, order, etc.

theme-development.md ~1200 File structure, JSON templates, sections, blocks, settings schema, layout

api-admin.md ~595 GraphQL queries/mutations, REST (legacy), OAuth, webhooks, rate limiting

api-storefront.md ~235 Storefront API, Ajax API, cart operations, Customer Account API

app-development.md ~760 CLI, app architecture, extensions, Polaris Web Components, deployment

functions.md ~300 Function types, Rust/JS targets, CLI workflow, Scripts migration

hydrogen.md ~375 Setup, routing, data loading, Storefront API, deployment

performance.md ~605 Images, JS, CSS, fonts, Liquid, third-party scripts, Core Web Vitals

debugging.md ~650 Liquid, JavaScript, API, cart, webhook, theme editor troubleshooting