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<!DOCTYPE html><html><head><meta charSet="utf-8" data-next-head=""/><title data-next-head="">What is Edge Runtime | Edge Runtime</title><meta name="robots" content="index,follow" data-next-head=""/><meta name="description" content="The Edge Runtime is a toolkit for developing, testing, and defining the runtime Web APIs for Edge infrastructure." data-next-head=""/><meta property="og:title" content="What is Edge Runtime | Edge Runtime" data-next-head=""/><meta property="og:description" content="The Edge Runtime is a toolkit for developing, testing, and defining the runtime Web APIs for Edge infrastructure." data-next-head=""/><meta name="theme-color" content="#111" media="(prefers-color-scheme: dark)" data-next-head=""/><style data-next-head=""> :root { --nextra-primary-hue: 212deg; --nextra-primary-saturation: 100%; --nextra-navbar-height: 4rem; --nextra-menu-height: 3.75rem; --nextra-banner-height: 2.5rem; } .dark { --nextra-primary-hue: 204deg; --nextra-primary-saturation: 100%; } 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dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50">Features<svg fill="none" viewBox="0 0 24 24" stroke="currentColor" class="nx-h-[18px] nx-min-w-[18px] nx-rounded-sm nx-p-0.5 hover:nx-bg-gray-800/5 dark:hover:nx-bg-gray-100/5"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7" class="nx-origin-center nx-transition-transform rtl:-nx-rotate-180 ltr:nx-rotate-90 rtl:nx-rotate-[-270deg]"></path></svg></button><div class="nx-transform-gpu nx-overflow-hidden nx-transition-all nx-ease-in-out motion-reduce:nx-transition-none"><div class="nx-transition-opacity nx-duration-500 nx-ease-in-out motion-reduce:nx-transition-none nx-opacity-100 ltr:nx-pr-0 rtl:nx-pl-0 nx-pt-1"><ul class="nx-flex nx-flex-col nx-gap-1 nx-relative before:nx-absolute before:nx-inset-y-1 before:nx-w-px before:nx-bg-gray-200 before:nx-content-[""] dark:before:nx-bg-neutral-800 ltr:nx-pl-3 ltr:before:nx-left-0 rtl:nx-pr-3 rtl:before:nx-right-0 ltr:nx-ml-3 rtl:nx-mr-3"><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/features/available-apis">Edge Runtime APIs</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/features/polyfills">Polyfills</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent 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[word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50">Packages<svg fill="none" viewBox="0 0 24 24" stroke="currentColor" class="nx-h-[18px] nx-min-w-[18px] nx-rounded-sm nx-p-0.5 hover:nx-bg-gray-800/5 dark:hover:nx-bg-gray-100/5"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 5l7 7-7 7" class="nx-origin-center nx-transition-transform rtl:-nx-rotate-180 ltr:nx-rotate-90 rtl:nx-rotate-[-270deg]"></path></svg></button><div class="nx-transform-gpu nx-overflow-hidden nx-transition-all nx-ease-in-out motion-reduce:nx-transition-none"><div class="nx-transition-opacity nx-duration-500 nx-ease-in-out motion-reduce:nx-transition-none nx-opacity-100 ltr:nx-pr-0 rtl:nx-pl-0 nx-pt-1"><ul class="nx-flex nx-flex-col nx-gap-1 nx-relative before:nx-absolute before:nx-inset-y-1 before:nx-w-px before:nx-bg-gray-200 before:nx-content-[""] dark:before:nx-bg-neutral-800 ltr:nx-pl-3 ltr:before:nx-left-0 rtl:nx-pr-3 rtl:before:nx-right-0 ltr:nx-ml-3 rtl:nx-mr-3"><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/cookies">@edge-runtime/cookies</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/format">@edge-runtime/format</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/jest-environment">@edge-runtime/jest-environment</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/jest-expect">@edge-runtime/jest-expect</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/node-utils">@edge-runtime/node-utils</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/ponyfill">@edge-runtime/ponyfill</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/primitives">@edge-runtime/primitives</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/runtime">edge-runtime</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/types">@edge-runtime/types</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/user-agent">@edge-runtime/user-agent</a></li><li class="nx-flex nx-flex-col nx-gap-1"><a class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50" href="/packages/vm">@edge-runtime/vm</a></li></ul></div></div></li><li class="nx-flex nx-flex-col nx-gap-1"><a href="https://github.com/vercel/edge-runtime/releases" target="_blank" rel="noreferrer" class="nx-flex nx-rounded nx-px-2 nx-py-1.5 nx-text-sm nx-transition-colors [word-break:break-word] nx-cursor-pointer [-webkit-tap-highlight-color:transparent] [-webkit-touch-callout:none] contrast-more:nx-border nx-text-gray-500 hover:nx-bg-gray-100 hover:nx-text-gray-900 dark:nx-text-neutral-400 dark:hover:nx-bg-primary-100/5 dark:hover:nx-text-gray-50 contrast-more:nx-text-gray-900 contrast-more:dark:nx-text-gray-50 contrast-more:nx-border-transparent contrast-more:hover:nx-border-gray-900 contrast-more:dark:hover:nx-border-gray-50">Changelog<span class="nx-sr-only nx-select-none"> (opens in a new tab)</span></a></li></ul></div></div></div><div class="nx-sticky nx-bottom-0 nx-bg-white dark:nx-bg-dark nx-mx-4 nx-py-4 nx-shadow-[0_-12px_16px_#fff] nx-flex nx-items-center nx-gap-2 dark:nx-border-neutral-800 dark:nx-shadow-[0_-12px_16px_#111] contrast-more:nx-border-neutral-400 contrast-more:nx-shadow-none contrast-more:dark:nx-shadow-none nx-border-t" data-toggle-animation="off"><div class="nx-grow nx-flex nx-flex-col"><button title="Change theme" class="nx-h-7 nx-rounded-md nx-px-2 nx-text-left nx-text-xs nx-font-medium nx-text-gray-600 nx-transition-colors dark:nx-text-gray-400 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nx-max-h-[calc(100vh-var(--nextra-navbar-height)-env(safe-area-inset-bottom))] ltr:-nx-mr-4 rtl:-nx-ml-4"><p class="nx-mb-4 nx-font-semibold nx-tracking-tight">On This Page</p><ul><li class="nx-my-2 nx-scroll-my-6 nx-scroll-py-6"><a href="#using-the-edge-runtime-locally" class="nx-font-semibold nx-inline-block nx-text-gray-500 hover:nx-text-gray-900 dark:nx-text-gray-400 dark:hover:nx-text-gray-300 contrast-more:nx-text-gray-900 contrast-more:nx-underline contrast-more:dark:nx-text-gray-50 nx-w-full nx-break-words">Using the Edge Runtime Locally</a></li></ul><div class="nx-mt-8 nx-border-t nx-bg-white nx-pt-8 nx-shadow-[0_-12px_16px_white] dark:nx-bg-dark dark:nx-shadow-[0_-12px_16px_#111] nx-sticky nx-bottom-0 nx-flex nx-flex-col nx-items-start nx-gap-2 nx-pb-8 dark:nx-border-neutral-800 contrast-more:nx-border-t contrast-more:nx-border-neutral-400 contrast-more:nx-shadow-none contrast-more:dark:nx-border-neutral-400"><a href="https://github.com/vercel/edge-runtime/issues/new?title=Feedback%20for%20%E2%80%9CWhat%20is%20Edge%20Runtime%E2%80%9D&labels=feedback" target="_blank" rel="noreferrer" class="nx-text-xs nx-font-medium nx-text-gray-500 hover:nx-text-gray-900 dark:nx-text-gray-400 dark:hover:nx-text-gray-100 contrast-more:nx-text-gray-800 contrast-more:dark:nx-text-gray-50">Question? Give us feedback →<span class="nx-sr-only nx-select-none"> (opens in a new tab)</span></a><a class="nx-text-xs nx-font-medium nx-text-gray-500 hover:nx-text-gray-900 dark:nx-text-gray-400 dark:hover:nx-text-gray-100 contrast-more:nx-text-gray-800 contrast-more:dark:nx-text-gray-50" href="https://github.com/vercel/edge-runtime/blob/main/docs/pages/index.mdx">Edit this page on GitHub</a></div></div></nav><div id="reach-skip-nav"></div><article class="nx-w-full nx-break-words nextra-content nx-flex nx-min-h-[calc(100vh-var(--nextra-navbar-height))] nx-min-w-0 nx-justify-center nx-pb-8 nx-pr-[calc(env(safe-area-inset-right)-1.5rem)]"><main class="nx-w-full nx-min-w-0 nx-max-w-6xl nx-px-6 nx-pt-4 md:nx-px-12"><div class="nextra-breadcrumb nx-mt-1.5 nx-flex nx-items-center nx-gap-1 nx-overflow-hidden nx-text-sm nx-text-gray-500 dark:nx-text-gray-400 contrast-more:nx-text-current"><div class="nx-whitespace-nowrap nx-transition-colors nx-font-medium nx-text-gray-700 contrast-more:nx-font-bold contrast-more:nx-text-current dark:nx-text-gray-100 contrast-more:dark:nx-text-current" title="Introduction">Introduction</div></div><h1 class="nx-mt-2 nx-text-4xl nx-font-bold nx-tracking-tight nx-text-slate-900 dark:nx-text-slate-100">The Edge Runtime</h1> <p class="nx-mt-6 nx-leading-7 first:nx-mt-0">The Edge Runtime is designed to help framework authors adopt edge computing and provide open-source tooling built on Web standards. It’s designed to be integrated into frameworks (like Next.js) and not for usage in application code.</p> <p class="nx-mt-6 nx-leading-7 first:nx-mt-0">The Edge Runtime is a subset of Node.js APIs, giving you compatibility and interoperability between multiple web environments. The project is designed to be compliant with standards developed by <a href="https://wintercg.org" target="_blank" rel="noreferrer" class="nx-text-primary-600 nx-underline nx-decoration-from-font [text-underline-position:from-font]">WinterCG<span class="nx-sr-only nx-select-none"> (opens in a new tab)</span></a> - a community group between Vercel, Cloudflare, Deno, Shopify, and more. The term “Edge” refers to the orientation toward instant serverless compute environments and not a specific set of locations.</p> <div class="grid grid-cols-2 gap-6 my-12 sm:grid-cols-3 "><div class="flex items-center space-x-4"><div><svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true" data-slot="icon" class="block w-8 h-8" style="height:24px;width:24px"><path stroke-linecap="round" stroke-linejoin="round" d="M16.023 9.348h4.992v-.001M2.985 19.644v-4.992m0 0h4.992m-4.993 0 3.181 3.183a8.25 8.25 0 0 0 13.803-3.7M4.031 9.865a8.25 8.25 0 0 1 13.803-3.7l3.181 3.182m0-4.991v4.99"></path></svg></div><div><div class="my-0 font-medium dark:text-white">Web APIs</div></div></div><div class="flex items-center space-x-4"><div><svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true" data-slot="icon" class="block w-8 h-8" style="height:24px;width:24px"><path stroke-linecap="round" stroke-linejoin="round" d="M7.864 4.243A7.5 7.5 0 0 1 19.5 10.5c0 2.92-.556 5.709-1.568 8.268M5.742 6.364A7.465 7.465 0 0 0 4.5 10.5a7.464 7.464 0 0 1-1.15 3.993m1.989 3.559A11.209 11.209 0 0 0 8.25 10.5a3.75 3.75 0 1 1 7.5 0c0 .527-.021 1.049-.064 1.565M12 10.5a14.94 14.94 0 0 1-3.6 9.75m6.633-4.596a18.666 18.666 0 0 1-2.485 5.33"></path></svg></div><div><div class="my-0 font-medium dark:text-white">Context isolation</div></div></div><div class="flex items-center space-x-4"><div><svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true" data-slot="icon" class="block w-8 h-8" style="height:24px;width:24px"><path stroke-linecap="round" stroke-linejoin="round" d="M12 16.5V9.75m0 0 3 3m-3-3-3 3M6.75 19.5a4.5 4.5 0 0 1-1.41-8.775 5.25 5.25 0 0 1 10.233-2.33 3 3 0 0 1 3.758 3.848A3.752 3.752 0 0 1 18 19.5H6.75Z"></path></svg></div><div><div class="my-0 font-medium dark:text-white">Easy to extend</div></div></div><div class="flex items-center space-x-4"><div><svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true" data-slot="icon" class="block w-8 h-8" style="height:24px;width:24px"><path stroke-linecap="round" stroke-linejoin="round" d="m3.75 13.5 10.5-11.25L12 10.5h8.25L9.75 21.75 12 13.5H3.75Z"></path></svg></div><div><div class="my-0 font-medium dark:text-white">Lightweight</div></div></div><div class="flex items-center space-x-4"><div><svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true" data-slot="icon" class="block w-8 h-8" style="height:24px;width:24px"><path stroke-linecap="round" stroke-linejoin="round" d="M3.75 3.75v4.5m0-4.5h4.5m-4.5 0L9 9M3.75 20.25v-4.5m0 4.5h4.5m-4.5 0L9 15M20.25 3.75h-4.5m4.5 0v4.5m0-4.5L15 9m5.25 11.25h-4.5m4.5 0v-4.5m0 4.5L15 15"></path></svg></div><div><div class="my-0 font-medium dark:text-white">Written in TypeScript</div></div></div><div class="flex items-center space-x-4"><div><svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" aria-hidden="true" data-slot="icon" class="block w-8 h-8" style="height:24px;width:24px"><path stroke-linecap="round" stroke-linejoin="round" d="M8.25 3v1.5M4.5 8.25H3m18 0h-1.5M4.5 12H3m18 0h-1.5m-15 3.75H3m18 0h-1.5M8.25 19.5V21M12 3v1.5m0 15V21m3.75-18v1.5m0 15V21m-9-1.5h10.5a2.25 2.25 0 0 0 2.25-2.25V6.75a2.25 2.25 0 0 0-2.25-2.25H6.75A2.25 2.25 0 0 0 4.5 6.75v10.5a2.25 2.25 0 0 0 2.25 2.25Zm.75-12h9v9h-9v-9Z"></path></svg></div><div><div class="my-0 font-medium dark:text-white">Node.js v16 or higher</div></div></div></div> <h2 class="nx-font-semibold nx-tracking-tight nx-text-slate-900 dark:nx-text-slate-100 nx-mt-10 nx-border-b nx-pb-1 nx-text-3xl nx-border-neutral-200/70 contrast-more:nx-border-neutral-400 dark:nx-border-primary-100/10 contrast-more:dark:nx-border-neutral-400">Using the Edge Runtime Locally<a href="#using-the-edge-runtime-locally" id="using-the-edge-runtime-locally" class="subheading-anchor" aria-label="Permalink for this section"></a></h2> <p class="nx-mt-6 nx-leading-7 first:nx-mt-0">When developing and testing locally, the Edge Runtime will polyfill Web APIs and ensure compatibility with the Node.js layer.</p> <p class="nx-mt-6 nx-leading-7 first:nx-mt-0">In production, the Edge Runtime uses the <a href="https://v8.dev/" target="_blank" rel="noreferrer" class="nx-text-primary-600 nx-underline nx-decoration-from-font [text-underline-position:from-font]">JavaScript V8 engine<span class="nx-sr-only nx-select-none"> (opens in a new tab)</span></a>, <strong>not</strong> Node.js, so there is <strong>no access</strong> to Node.js APIs.</p> <p class="nx-mt-6 nx-leading-7 first:nx-mt-0">Get started using Edge Runtime:</p> <ul class="nx-mt-6 nx-list-disc first:nx-mt-0 ltr:nx-ml-6 rtl:nx-mr-6"> <li class="nx-my-2"><a class="nx-text-primary-600 nx-underline nx-decoration-from-font [text-underline-position:from-font]" href="/features/available-apis">Explore the available APIs</a></li> <li class="nx-my-2"><a class="nx-text-primary-600 nx-underline nx-decoration-from-font [text-underline-position:from-font]" href="/packages/runtime">Integrate it in your project</a></li> <li class="nx-my-2"><a class="nx-text-primary-600 nx-underline nx-decoration-from-font [text-underline-position:from-font]" href="/packages/jest-environment">Test your code with Jest</a> or <a href="https://vitest.dev/config/#environment" target="_blank" rel="noreferrer" class="nx-text-primary-600 nx-underline nx-decoration-from-font [text-underline-position:from-font]">Vitest<span class="nx-sr-only nx-select-none"> (opens in a new tab)</span></a></li> </ul><div class="nx-mt-16"></div><div class="nx-mb-8 nx-flex nx-items-center nx-border-t nx-pt-8 dark:nx-border-neutral-800 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