Polyfills

The Edge Runtime is built on top of Web APIs available in Node.js.

The minimum Node.js version supported is v14.6.0 that is mapped to ES2019.

Under the hood, the following Web APIs are used by the Edge Runtime:

polyfill	node14	node16	node18
util.types (opens in a new tab)	x
WebCrypto (opens in a new tab)	x
AbortController, AbortSignal, DOMException (opens in a new tab)	x
base64 (opens in a new tab)	x
fetch, Request, Response (opens in a new tab)	x	x
URLPattern (opens in a new tab)	x	x	x
WebStreams (opens in a new tab)	x	x	x

The Edge Runtime polyfills missing APIs for backward compatibility with older Node.js versions.

In the future, Node.js will become a superset of the Edge Runtime with built-in support for the available APIs.