The headless commerce
glossary.

Permanent URL redirect. Preserves SEO authority when URLs change (like during a migration).

Running two variants of a page element (button, headline, layout) against each other to see which performs better.

An AI system that autonomously takes actions to achieve a goal. Handles WhatsApp chats, voice calls, or support tickets 24/7.

Rules and constraints that prevent AI from taking unauthorized actions or generating inappropriate content.

Average Order Value — total revenue divided by number of orders. Increasing AOV is often easier than increasing traffic.

Next-generation image format with better compression than WebP and JPEG. Supported by most modern browsers.

Business-to-Business — selling to companies rather than consumers. Requires different UX than D2C.

Clearing cached content when the underlying data changes. Trickier in headless architectures.

The preferred URL when the same content is accessible at multiple URLs. Prevents SEO penalties for duplicate content.

When a user adds items to cart but doesn't complete checkout. Industry average: ~70%.

Automated sequences (email, SMS, WhatsApp) that nudge users back to complete their abandoned cart.

Content Delivery Network — a network of servers distributed globally to serve content from the location closest to the user.

Shopify Plus feature that lets you customize the checkout flow with apps and custom UI. Only available on Plus.

Cumulative Layout Shift — measures visual stability. How much content shifts around as the page loads. Google recommends under 0.1.

Breaking JavaScript bundles into smaller chunks loaded on demand, reducing initial page weight.

An approach where you assemble best-of-breed services (Shopify for cart, Sanity for content, Algolia for search) instead of using one monolithic platform.

The percentage of visitors who complete a desired action. For D2C e-commerce, typically 1.5%–3%.

Google's three key metrics for user experience: LCP, CLS, and INP. These directly affect search rankings.

The minimum CSS required to render above-the-fold content. Inlined in the HTML to prevent render-blocking.

Conversion Rate Optimization — the practice of increasing the percentage of visitors who complete a goal (purchase, signup).

Conversion Rate — see CRO. Sometimes used interchangeably.

Direct-to-Consumer — brands that sell directly to customers, bypassing traditional retail intermediaries.

Direct-to-Consumer (US-preferred spelling). Same meaning as D2C.

Serverless runtime deployed to CDN edge nodes (like Vercel Edge). Serves requests from the closest geographic location to the user.

Numerical representation of text/data that captures meaning. Enables semantic similarity search.

Trigger that fires when a user is about to leave the page. Often used to show a last-chance offer.

First Contentful Paint — when the browser renders the first piece of DOM content. Target: under 1.8 seconds.

Reducing a font file to only the glyphs actually used on a page (often English alphabet + digits). Cuts font file size by 80%+.

AI ability to invoke external functions (create order, send email) based on conversation. Enables agents to take real actions.

The sequence of steps a user takes from landing to purchase. Each step has a drop-off rate.

Gross Merchandise Value — total sales value over a period. Often used as a company scale metric.

Query language for APIs. Lets you request exactly the data you need — used by Shopify Storefront API.

Content management system that provides content via API instead of templates. Sanity and Contentful are examples.

An architecture where the frontend (storefront) is decoupled from the backend (commerce engine). Lets you use any technology for the frontend while keeping Shopify as the backend.

Visual representation of where users click, scroll, and hover. Reveals what attracts attention.

HTML attribute that tells search engines about page language and region variants. Critical for international SEO.

Shopify's official React framework for building custom storefronts. Built on top of Remix, now superseded by our Next.js-first approach.

React components and hooks for Shopify's Storefront API. Used in headless builds to handle cart, product, and search logic.

Interaction to Next Paint — measures how quickly the page responds to taps and clicks. Google recommends under 200ms.

Incremental Static Regeneration — Next.js feature that combines static performance with dynamic updates. Pages revalidate in the background.

Background refresh of static pages in Next.js. Combines static speed with dynamic content freshness.

JavaScript, APIs, Markup. A modern architecture where the frontend is pre-rendered and enhanced with APIs. Headless commerce is a JAMstack implementation.

Deferring the loading of images and other resources until they are needed (usually when entering the viewport).

Largest Contentful Paint — measures how long it takes for the largest visible element (usually a hero image or heading) to render. Google recommends under 2.5 seconds on mobile.

Google's automated score (0–100) covering performance, accessibility, best practices, and SEO. 90+ is considered excellent.

Shopify's templating language for traditional themes. Slow, limited, and the core reason brands migrate to headless.

Large Language Model — AI models (GPT-4, Claude, Llama) trained on massive text data. Power modern AI agents.

Microservices, API-first, Cloud-native, Headless. An enterprise framework for building composable commerce systems.

Custom data fields that extend Shopify's default product/order/customer schema. Essential for storing custom attributes.

Displaying prices in local currencies based on user location. Requires multi-region architecture.

Testing multiple variations of multiple elements simultaneously. More complex than A/B testing.

Crafting effective instructions for AI models. Determines the quality and reliability of AI outputs.

Retrieval-Augmented Generation — technique where an LLM answers questions using your own data (products, policies) as context.

Resources (CSS, JS) that must load before the browser can render the page. A major cause of slow LCP.

Serving different image sizes based on viewport width. Prevents wasting bandwidth on mobile.

React Server Components — components that render on the server only, reducing JavaScript sent to the browser. Default in Next.js 15 App Router.

Recording of a real user's session — clicks, scrolls, mouse movements. Shows what users actually do.

Server-side JavaScript functions that run inside Shopify to customize discounts, shipping, and payment logic.

Shopify's enterprise tier with higher API limits, checkout extensibility, and multi-store features. Required for large headless builds.

Stock Keeping Unit — a unique identifier for each product variant (size, color, etc.).

Static Site Generation — building HTML pages at build time. Fastest possible performance, but requires rebuilds to update.

Server-Side Rendering — generating HTML on the server for every request. Better for SEO than client-side rendering.

Cache strategy where stale content is served immediately while fresh content is fetched in the background.

Shopify's GraphQL API that lets you query products, collections, carts, and checkout from any frontend. Core to any headless build.

JavaScript loaded from an external domain (analytics, chat, reviews). Each one can add 100–500ms of load time.

Build-time optimization that removes unused code from JavaScript bundles.

Time to First Byte — the time between a browser request and the first byte of the response. A good target is under 800ms.

Database optimized for storing and searching vector embeddings. Used for semantic search and RAG.

HTTP callback sent by a service when an event occurs. Used to sync data between systems in real time.

HTTP callbacks that Shopify sends when events happen (order created, product updated). Used to sync data with external systems.

Modern image format with 25–35% smaller files than JPEG at similar quality. Broadly supported.