# Upgrading Checkout Blocks app to Polaris web components

DevFeed: [Upgrading Checkout Blocks app to Polaris web components](<https://devfeed.tech/articles/upgrading-checkout-blocks-app-to-polaris-web-components-1662.md>)

Original publisher: [Read original article](<https://shopify.engineering/upgrading-checkout-blocks-app-to-polaris-web-components>)

Author: Justin Henricks

Published: 2026-07-16T17:19:40Z

Content type: article

Language: en

Sources: [Shopify Engineering](<https://devfeed.tech/sources/shopify-engineering.md>), [Shopify Engineering - Shopify Engineering](<https://devfeed.tech/sources/shopify-engineering-shopify-engineering.md>)

Topics: [Latency](<https://devfeed.tech/topics/latency.md>), [React](<https://devfeed.tech/topics/react.md>), [GraphQL](<https://devfeed.tech/topics/graphql.md>), [telemetry](<https://devfeed.tech/topics/telemetry.md>), [API](<https://devfeed.tech/topics/api.md>)

Tags: [api](<https://devfeed.tech/tags/api.md>), [apis](<https://devfeed.tech/tags/apis.md>), [architecture](<https://devfeed.tech/tags/architecture.md>), [checkout](<https://devfeed.tech/tags/checkout.md>), [latency](<https://devfeed.tech/tags/latency.md>), [performance](<https://devfeed.tech/tags/performance.md>), [react](<https://devfeed.tech/tags/react.md>), [telemetry](<https://devfeed.tech/tags/telemetry.md>), [typescript](<https://devfeed.tech/tags/typescript.md>), [web](<https://devfeed.tech/tags/web.md>)

## AI overview

Checkout Blocks migrated five high-traffic checkout extensions from Shopify's legacy Remote UI and React-based path to remote-dom, Polaris web components, Preact, and TypeScript. The upgrade reduced transferred bundle sizes by 40% to 85% and improved extension loading performance.

## Source excerpt

We moved five high-traffic checkout extensions to remote-dom and Polaris web components, cutting bundle sizes drastically and making checkout faster.