Shopify Re-Architects Theme Code to Support AI Agents

Shopify is redesigning its storefront theme architecture to better accommodate AI agents, according to reporting from The Register. The company is developing a successor to its current JSON-heavy base theme, Horizon, moving toward a system primarily composed of HTML and Shopify's block-based Liquid templating language.

Ben Sehl, Shopify product director for storefronts, stated on X that leading AI models are already token-efficient and expressive with HTML. The shift aims to eliminate the complexity created by serialized configuration; Sehl noted that when templates became JSON, they ceased to be a strong developer surface and instead became "auto-saved output."

The redesign follows the growth of Shopify Sidekick, an AI assistant used by 20% of Shopify merchants to make 25 million edits this year. To optimize for these agents, Shopify is prioritizing easy-to-read code and explicit contracts. The resulting new theme contains 93% fewer lines of code than Horizon.

Technical updates include a new Liquid syntax and parser, a composable block tag for nested parameters, and a partial primitive to update specific page regions without full re-renders. Sehl indicated that this primitive will allow the company to remove thousands of lines of reactivity code from Horizon. Additionally, Shopify has established 20 new rules governing file-size limits, complexity, and validation to ensure generated themes adhere to company policies.