Shopify Theme Devtools

A powerful in-browser developer tools panel for Shopify theme development. Inspect Liquid objects, evaluate expressions, explore metafields, manipulate cart state, detect Liquid errors, and much more — all without leaving the browser.

Table of Contents

• Features
• Quick Start
• Keyboard Shortcuts
• Panel Reference
• Configuration
• Development
• How It Works
• Tech Stack
• Browser Support
• Contributing
• License

Features

Core Panels

• AI Assistant — GPT-powered theme debugging with full context access (cart, metafields, analytics, accessibility, and more)
• Objects Inspector — Browse shop, product, collection, customer, cart and more with deep search and collapsible tree view
• Metafields Viewer — Explore metafields across all resources and namespaces with type labels
• Cart Panel — Real-time cart state with add/remove/quantity controls, cart history with restore, and attribute editing
• Console — Chrome DevTools-style console with Liquid expression evaluator, and autocomplete
• Localization — Markets, currencies, languages, and country data with quick switcher
• SEO Inspector — Meta tags, Open Graph, Twitter Cards, and structured data (JSON-LD) validation
• Analytics Viewer — Captures GA4, Facebook Pixel, TikTok, Pinterest, Snapchat, Klaviyo, Shopify Analytics, and dataLayer events
• Accessibility Scanner — WCAG compliance checker with issue severity, suggested fixes, and score
• Storage Inspector — Browse and edit localStorage, sessionStorage, and cookies
• Apps Panel — Lists installed Shopify apps detected on the page
• Info Panel — Theme details, template info, and request metadata

Objects Inspector

Browse and search through all Liquid objects with a collapsible tree view. Click any key to copy its Liquid path.

Console Panel

A powerful Liquid debugger combining error detection and expression evaluation.

Liquid Error Detection:

• Liquid Errors — Detects Liquid error: and Liquid syntax error: messages in page content
• Drop Object Leaks — Finds raw Drop objects rendered on page (ProductDrop, #<ProductDrop:0x...>)
• Asset Errors — Missing snippets, images, and asset files
• Schema Errors — Invalid JSON in section schemas
• JSON Filter Errors — Detects {"error":"..."} output from failed | json filters
• Form Errors — Missing product/customer objects for forms
• Smart Hints — Context-aware fix suggestions for each error type

Expression Evaluator:

Cart Snapshots

Track cart state changes over time and restore any previous snapshot with a single click.

Console Expression Evaluator

The Console panel includes an interactive expression evaluator for testing Liquid paths:

> product.title
"Classic Cotton T-Shirt"

> product.variants[0].price | money
"$29.99"

> cart.items | size
3

> shop.name | upcase
"MY AWESOME STORE"

Features:

• Autocomplete — Suggests paths as you type with Tab completion
• Liquid Filters — Supports upcase, downcase, money, size, first, last, and 50+ filters
• Array Access — Navigate arrays with bracket notation: product.variants[0].title
• Live Data — Uses current cart and product data, not stale page load values
• Command History — Use arrow keys to navigate previous expressions

Cart Panel

• Live Updates — Cart state updates in real-time as items are added/removed
• Quantity Controls — Adjust item quantities directly
• Cart History — View previous cart states with timestamps and restore any snapshot
• Attribute Editor — Modify cart attributes and notes
• Diff View — See what changed between cart states
• Scenario Builder — Create and save cart scenarios for quick testing
• Cart Tests — Write validation rules to automatically test cart items

Cart Tests

The Cart Tests feature lets you create custom validation rules to ensure cart items meet your business requirements. Tests can be run manually or automatically whenever the cart changes.

Rule Types:

| Type | Description | Example | |------|-------------|---------| | Property Dependency | If item has property X, must have properties Y, Z | GWP items require _gwp_price and _gwp_source | | Field Value | If field equals X, another field must meet condition | Gift Cards must have quantity = 1 | | Cart Composition | If item X exists, item Y must also exist | Electronics require warranty item | | Quantity | Min/max/multiple constraints per-item or cart-total | Max 10 per item, cart total max 50 |

Features:

• Pre-built Templates — 16 ready-to-use templates for common scenarios
• Auto-run — Toggle to run all tests whenever cart changes
• Import/Export — Save and share test configurations as JSON
• Inline Results — Pass/fail badges show test status at a glance

AI Assistant

An intelligent GPT-powered assistant that understands your Shopify theme context. Ask questions, debug issues, and generate Liquid code with full access to your page data.

Setup:

1. Open the AI panel
2. Enter your OpenAI API key (stored locally, never sent anywhere except OpenAI)
3. Start asking questions

What AI Can Access:

• Page/template info, shop details, current resource (product/collection/page)
• Customer data (if logged in)
• Cart state and cart history
• Metafields for all resources
• Section schemas (from theme editor data)
• HTML structure of the page
• Network requests and responses
• Cookies, localStorage, sessionStorage
• Liquid errors detected on the page
• Accessibility scan results
• Analytics events (GA4, Facebook Pixel, TikTok, Pinterest, Snapchat, Klaviyo, Shopify, dataLayer)

Context Modes: | Mode | Description | |------|-------------| | Auto | Smart detection - includes relevant context based on your question | | Minimal | Basic page info and cart only (faster responses) | | Full | Everything including cookies, storage, analytics, accessibility | | Custom | Pick exactly which context to include |

Example Questions:

• "What data is available on this page?"
• "Help me write Liquid to display the product price with compare at price"
• "Why isn't my add to cart button working?"
• "What analytics events are firing on this page?"
• "Are there any accessibility issues I should fix?"

Features:

• Streaming responses — See answers as they're generated
• Syntax highlighting — Code blocks with Liquid, JavaScript, and JSON highlighting
• Conversation history — Per-page conversations persist in session storage
• Search — Find text across your conversation history
• Copy code — One-click copy for any code block

Liquid Error Detection

Automatically scans the page for common Liquid issues:

• Liquid error: and Liquid syntax error: messages
• Drop object leaks (#<ProductDrop:0x...>)
• Missing snippets and assets
• Schema validation errors
• Deprecation warnings

Analytics Panel

Captures and inspects analytics events from multiple tracking providers in real-time.

Supported Providers: | Provider | Detection | |----------|-----------| | Google Analytics 4 | gtag() calls | | Google Analytics Universal | ga() calls | | Facebook Pixel | fbq() calls | | TikTok Pixel | ttq.track() calls | | Pinterest Tag | pintrk() calls | | Snapchat Pixel | snaptr() calls | | Klaviyo | _learnq.push() calls | | Shopify Analytics | Shopify.analytics.publish() | | Shopify Web Pixels | analytics.subscribe() | | DataLayer | dataLayer.push() |

Features:

• Live capture — Events appear as they fire
• Conversion tracking — Highlights purchase, add_to_cart, and other conversion events
• Filtering — Filter by provider or search event names/data
• Deduplication — Groups duplicate events fired within 500ms
• Export — Download captured events as JSON
• Pause/Resume — Stop capturing to analyze current events
• Persistence — Events persist across page navigations (session storage)

Network Panel

Captures and inspects Shopify API requests with powerful debugging tools:

• Request Logging — Auto-captures cart, product, collection, search, and GraphQL requests
• Request Editor — Edit and resend requests with modified method, URL, headers, and body
• Replay — Re-execute any captured request with one click
• Cart State Diff — See exactly what changed in the cart after mutations (items added/removed/changed)
• Copy as cURL/Fetch — Export requests for debugging or sharing
• Persistence — Last 32 requests are saved to localStorage and restored on reload
• GraphQL Prettifier — Syntax-highlighted, formatted GraphQL queries
• Error Diagnosis — Smart suggestions for common cart and API errors (out of stock, invalid variants, quantity limits)

Tab Customization

Customize your devtools layout like Chrome DevTools:

• Right-click any tab to show/hide it
• Drag tabs to reorder them
• Preferences tab cannot be hidden (ensures you can always restore tabs)
• "Reset to Defaults" restores original tab order and visibility
• Hidden tabs are completely unloaded from DOM (saves memory/CPU)

Quick Start

Option A: Using npm (Recommended)

# Run directly with npx (no install needed)
npx shopify-theme-devtools init

# Or install globally for repeated use
npm install -g shopify-theme-devtools
shopify-theme-devtools init

This copies the Liquid snippet to your snippets/ folder. Then add this line to layout/theme.liquid just before </body>:

{% render 'theme-devtools-bridge' %}

Or use --inject to add it automatically:

npx shopify-theme-devtools init --inject

CLI Options

| Option | Description | |--------|-------------| | --local | Copy JS/CSS to assets/ folder instead of using CDN | | --inject | Automatically add render tag to layout/theme.liquid | | --force | Overwrite existing files without prompting |

The CLI automatically detects and injects your metafields.json schema from .shopify/metafields.json (or theme root), enabling devtools to show all defined metafields.

Syncing Metafields

When your metafields change over time, run the sync command to update the schema without overwriting other customizations:

npx shopify-theme-devtools sync

# Examples
npx shopify-theme-devtools init                    # Uses CDN (recommended)
npx shopify-theme-devtools init --local            # Self-hosted assets
npx shopify-theme-devtools init --local --inject   # Self-hosted + auto-inject

Option B: Manual Download

# Download directly
curl -o snippets/theme-devtools-bridge.liquid \
  https://raw.githubusercontent.com/yakohere/shopify-theme-devtools/main/src/liquid/theme-devtools-bridge.liquid

Then add {% render 'theme-devtools-bridge' %} to layout/theme.liquid before </body>.

You're done!

The devtools panel automatically appears on unpublished/development themes only. It's safe to commit — it won't render on your live published theme.

Keyboard Shortcuts

| Action | Shortcut | |--------|----------| | Toggle Panel | Cmd+Shift+D (Mac) / Ctrl+Shift+D (Windows) | | Copy Liquid Path | Click any property key in Objects panel | | Evaluate Expression | Enter in Console input | | Autocomplete | Tab in Console input | | Command History | ↑ / ↓ in Console input | | Show/Hide Tabs | Right-click any tab | | Reorder Tabs | Drag and drop tabs |

Panel Reference

| Panel | Description | |-------|-------------| | AI | GPT-powered assistant with full theme context access | | Objects | Inspect all Liquid objects with search and tree navigation | | Metafields | Browse metafields by resource (product, collection, shop, etc.) | | Cart | Live cart state, history, scenarios, tests, and manipulation tools | | Locale | Markets, currencies, languages with locale switching | | Analytics | Live event capture for GA4, FB Pixel, TikTok, Pinterest, Klaviyo, Shopify | | Accessibility | WCAG compliance scanner with score and suggested fixes | | SEO | Meta tags, Open Graph, Twitter Cards, JSON-LD structured data | | Apps | Installed Shopify apps detected on the page | | Network | API request monitor with edit/replay, cart diffs, and error diagnosis | | Console | Logs, errors, and Liquid expression evaluator | | Cookies | Browser cookies with expiration and flags | | Storage | localStorage and sessionStorage key-value pairs | | Info | Theme info, template details, request metadata | | Preferences | Panel position, theme (dark/light), font scale, shortcuts |

Configuration

Local Development

For local development with hot reload:

1. Edit the bridge snippet to enable local mode:

{%- assign devtools_local = true -%}

2. Run the dev server:

npm run dev  # Starts at localhost:9999

Metafields Schema

To show all defined metafields (not just ones with values), paste your theme's metafields.json content into the bridge snippet:

{%- capture devtools_metafields_schema -%}
{
  "product": [
    { "namespace": "custom", "key": "care_instructions", "type": "single_line_text_field" }
  ]
}
{%- endcapture -%}

Theme Settings

Configure which theme settings to expose by editing the devtools_settings_config in the bridge snippet:

{%- capture devtools_settings_config -%}
colors_accent_1|color|Accent 1|colors
type_header_font|font_picker|Header font|typography
page_width|range|Page width|layout
{%- endcapture -%}

Development

# Install dependencies
npm install

# Start dev server with hot reload (localhost:9999)
npm run dev

# Build for production
npm run build

# Preview production build
npm run preview

Project Structure

src/
├── liquid/
│   └── theme-devtools-bridge.liquid  # Liquid snippet for themes
├── scripts/
│   ├── components/
│   │   ├── theme-devtools.js         # Main component with tab management
│   │   ├── object-inspector.js       # Tree view inspector
│   │   └── panels/                   # Panel components (ai, cart, analytics, etc.)
│   ├── lib/
│   │   └── cart-test-templates.js    # Pre-built cart test templates
│   ├── services/
│   │   ├── ai.js                     # OpenAI API integration
│   │   ├── analytics.js              # Analytics event interceptor
│   │   ├── accessibility.js          # Accessibility scanning service
│   │   ├── cart.js                   # Cart API with history
│   │   ├── product.js                # Product API (variants/images)
│   │   ├── context.js                # Liquid context parser
│   │   ├── context-serializer.js     # AI context serialization
│   │   ├── expression-evaluator.js   # Liquid expression engine
│   │   ├── network-interceptor.js    # Fetch/XHR interceptor with persistence
│   │   └── settings.js               # User preferences
│   └── styles/
│       └── theme.js                  # CSS variables and themes
└── styles/
    └── main.css

How It Works

1. Context Extraction — The Liquid bridge renders theme objects, metafields, and settings as a JSON blob
2. Async Data Loading — Product variants/images and cart data are fetched via Shopify's JSON APIs for live data
3. Expression Evaluation — Uses LiquidJS to evaluate Liquid expressions with Shopify-specific filters
4. Shadow DOM Isolation — All styles are scoped to prevent conflicts with theme CSS
5. Session Persistence — Logs, cart history, and preferences persist across page navigations

Security

• Only renders on unpublished themes (theme.role != 'main')
• Customer emails are partially masked
• No data is sent to external servers
• All processing happens client-side

Tech Stack

• Lit — Lightweight Web Components
• LiquidJS — Liquid template engine
• Vite — Fast build tooling

Browser Support

• Chrome 90+
• Firefox 90+
• Safari 14+
• Edge 90+

Contributing

Contributions are welcome! Please read our Contributing Guide for details.

License

MIT — Built by @yakohere