Chrome's XSLT removal: what breaks and how to fix it

What XSLT is

XSLT (Extensible Stylesheet Language Transformations) is a language for turning one XML document into another document, usually HTML. An XML file can name a stylesheet in its first lines with an <?xml-stylesheet?> instruction, and the browser runs the transformation before showing the result. That is how an XML sitemap or an RSS feed can open as a tidy, readable page while staying plain XML for the programs that consume it. Browsers support XSLT 1.0, a standard from 1999, and JavaScript can run the same engine directly through the XSLTProcessor API.

The timeline

These are the milestones in Chrome's deprecation notice, as checked on October 4, 2026. Treat the calendar dates as the reference; milestone numbers have been renumbered before.

Chrome's notice also says the Firefox and WebKit projects have indicated plans to remove XSLT from their engines. Neither had announced a date by October 2026.

What breaks

Two things go away in the browser: processing of the <?xml-stylesheet?> instruction, and the XSLTProcessor object in JavaScript. Here is how that shows up in practice.

Styled XML sitemaps

WordPress core, Yoast SEO, Rank Math and many other tools attach an XSL stylesheet to the sitemaps they generate, so a person opening sitemap.xml sees a table of URLs and dates. In Chrome that table becomes raw XML. The sitemap still works: search engines read the XML and never apply the stylesheet, so submission, crawling and indexing are unaffected. Only the human view changes.

Styled RSS and Atom feeds

Many blogs and podcasts style their feed so that a visitor who clicks it gets a friendly page with a "copy this into your reader" note instead of a wall of tags. Feed readers ignore the stylesheet, so subscribers notice nothing; people who open the feed in Chrome see raw XML.

Web apps that call XSLTProcessor

Some applications, often older intranet tools, admin panels and document viewers, build their screens in JavaScript with new XSLTProcessor(). Without the API those scripts stop with this error, and the screen stays blank or half-drawn:

Uncaught ReferenceError: XSLTProcessor is not defined

The XSLTProcessor is not defined guide covers this case for developers, with code.

Local XML files and device reports

XML reports opened from disk, such as test results, e-invoices and exports from accounting or lab software, and status pages served by routers, printers and industrial devices often depend on an XSL file sitting next to them. These are the hardest to fix, because the person viewing them usually can't change the software that produced them.

How to tell if you are affected

• Open your sitemap and feed URLs, view the source, and look for an <?xml-stylesheet line near the top.
• Search your code and templates for XSLTProcessor and xml-stylesheet.
• Open the pages in Chrome with the developer console visible; Chrome logs a deprecation warning when XSLT is used.
• Preview the result now: in a current Chrome, open chrome://flags/#xslt, set it to Disabled, and relaunch. You will see what visitors see after November 17.

Options for site owners

If you publish the XML, you can make the problem go away for every visitor. Pick by how much the styled view matters.

1. Transform on the server. Run the same stylesheet on your server (libxslt, Saxon, .NET, Java and PHP all can) and send HTML. Visitors get the same page with no browser dependency, and machines still get the XML at its own URL.
2. Publish an HTML version. For sitemaps and feeds, a normal HTML page that lists the same URLs or episodes often serves people better than a styled XML file, and it can be linked from your navigation.
3. Drop the stylesheet line. If nobody needs the styled view, remove the <?xml-stylesheet?> instruction. Chrome then shows the XML in its plain viewer, and machine consumers see no change. SEO plugins may offer a setting for this; check before editing generated files.
4. Load a polyfill library. Chrome's deprecation notice points to xslt-polyfill, an open-source library that runs libxslt compiled to WebAssembly in the page. It restores XSLTProcessor for your scripts; its README explains how to use it with XML documents.
5. Join the origin trial, to buy time. Registering your origin for Chrome's origin trial keeps native XSLT working on your site until August 17, 2027. It is a bridge to one of the options above, not a fix.

Options for visitors and IT teams

If you only read the XML and can't change the site that serves it, the fix has to live in your browser.

• An XSLT polyfill for Chrome, as an extension. An extension can detect XML that names a stylesheet and apply it for you. XSLT Prism does this with libxslt compiled to WebAssembly, running on your device, and restores XSLTProcessor on the sites you choose. It also includes an XML viewer and an XSLT tester for files without a stylesheet and for debugging your own.
• The XSLTEnabled policy, for managed browsers. Administrators can set the XSLTEnabled enterprise policy to keep native XSLT on company machines until August 17, 2027. Plan the replacement before then.
• Another browser, for now. Firefox and Safari still apply XSLT as of October 2026, but both engines have signalled that removal is coming.

After August 17, 2027

Once the origin trial and enterprise policy end, Chrome has no built-in way back. What keeps working is what doesn't depend on the browser's engine: transforms on the server, HTML versions of the content, a polyfill library on pages you control, and extensions on machines you use. If you rely on styled XML today, the months before that date are the time to pick one.