---
title: Transform HTML quickly with streaming content
description: HTMLRewriter now supports streamed content for more efficient replacement of HTML elements
image: https://developers.cloudflare.com/changelog-preview.png
---
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## Transform HTML quickly with streaming content
Jan 31, 2025
[ Workers ](https://developers.cloudflare.com/workers/)
You can now transform HTML elements with streamed content using [HTMLRewriter](https://developers.cloudflare.com/workers/runtime-apis/html-rewriter).
Methods like `replace`, `append`, and `prepend` now accept [Response](https://developers.cloudflare.com/workers/runtime-apis/response/) and [ReadableStream](https://developers.cloudflare.com/workers/runtime-apis/streams/readablestream/)values as [Content](https://developers.cloudflare.com/workers/runtime-apis/html-rewriter/#global-types).
This can be helpful in a variety of situations. For instance, you may have a Worker in front of an origin, and want to replace an element with content from a different source. Prior to this change, you would have to load all of the content from the upstream URL and convert it into a string before replacing the element. This slowed down overall response times.
Now, you can pass the `Response` object directly into the `replace` method, and HTMLRewriter will immediately start replacing the content as it is streamed in. This makes responses faster.
* [ JavaScript ](#tab-panel-2783)
* [ TypeScript ](#tab-panel-2784)
index.js
```
class ElementRewriter { async element(element) { // able to replace elements while streaming content // the fetched body is not buffered into memory as part // of the replace let res = await fetch("https://upstream-content-provider.example"); element.replace(res); }}
export default { async fetch(request, env, ctx) { let response = await fetch("https://site-to-replace.com"); return new HTMLRewriter() .on("[data-to-replace]", new ElementRewriter()) .transform(response); },};
```
index.ts
```
class ElementRewriter { async element(element: any) { // able to replace elements while streaming content // the fetched body is not buffered into memory as part // of the replace let res = await fetch('https://upstream-content-provider.example'); element.replace(res); }}
export default { async fetch(request, env, ctx): Promise { let response = await fetch('https://site-to-replace.com'); return new HTMLRewriter().on('[data-to-replace]', new ElementRewriter()).transform(response); },} satisfies ExportedHandler;
```
For more information, see the [HTMLRewriter documentation](https://developers.cloudflare.com/workers/runtime-apis/html-rewriter).
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