XSLT Transformer

XSLT Transformer

Transform XML documents using XSLT stylesheets. Live preview of rendered HTML. Built-in templates for tables, cards, lists. Free online XSLT processor

XSLT is the XML transformation language that nobody learns voluntarily and that powers half the legacy enterprise systems still in production. The interesting nuance: XSLT 1.0 ships in every browser (via libxslt or Saxon), XSLT 2.0/3.0 require Saxon and are vastly more powerful (sequences, functions, JSON support added in 3.0), and they are not interchangeable. This tool runs XSLT 1.0 in-browser using the browser's native XSLTProcessor — fast, well-debugged, and exactly what your legacy XML pipelines actually use.

XSLT 1.0 vs 2.0 vs 3.0

  • XSLT 1.0 (1999) — what every browser ships. Templates match XPath patterns; output is XML/HTML/text. No user-defined functions, no sequences, no grouping primitives (xsl:for-each-group). Most production legacy XSLT is 1.0.
  • XSLT 2.0 (2007) — required Saxon. Adds xsl:function, sequences, xsl:for-each-group, regex (matches, replace, tokenize), date/time types. Significantly more powerful.
  • XSLT 3.0 (2017) — current standard. Adds JSON support (xsl:stream JSON parsing, json-to-xml), streaming for huge documents, packages for modularization, higher-order functions. Saxon HE/EE/PE only.
  • Browser support: 1.0 only. For 2.0/3.0, use Saxon-JS in browser or command-line Saxon.

Working example: XML to HTML

Input

XML:
<books>
  <book id="1">
    <title>The Pragmatic Programmer</title>
    <author>Andy Hunt</author>
    <year>1999</year>
  </book>
  <book id="2">
    <title>Clean Code</title>
    <author>Robert Martin</author>
    <year>2008</year>
  </book>
</books>

XSLT (1.0):
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:template match="/">
    <html><body>
      <h1>Books</h1>
      <ul>
        <xsl:for-each select="books/book">
          <li>
            <xsl:value-of select="title"/> by <xsl:value-of select="author"/>
            (<xsl:value-of select="year"/>)
          </li>
        </xsl:for-each>
      </ul>
    </body></html>
  </xsl:template>
</xsl:stylesheet>

Output

<html><body>
  <h1>Books</h1>
  <ul>
    <li>The Pragmatic Programmer by Andy Hunt (1999)</li>
    <li>Clean Code by Robert Martin (2008)</li>
  </ul>
</body></html>

XSLT 1.0 is template-match-based — each `xsl:template match="..."` rule applies to nodes matching the XPath. Verbose for what JS does in 5 lines, but standardized and deterministic.

When XSLT still makes sense

  • Existing enterprise pipelines — SOAP/XML messaging, BizTalk, MuleSoft, government data exchange. Already implemented in XSLT; rewriting in Node/Python is large project with minimal benefit.
  • XML-heavy domains — SVG transformation, OOXML (Office Open XML) document processing, RSS/Atom feed conversion. Native XML manipulation.
  • Bank / healthcare / insurance — many standards are XML-based (HL7, FpML, FIXML). Industry tooling assumes XSLT.
  • Cross-platform deterministic — XSLT is a W3C standard; every conforming processor produces the same output. Compare to JavaScript transformation where runtime version, library version, and host OS can change behavior.
  • Documentation systems — DITA, DocBook, JATS use XSLT for rendering to HTML / PDF / EPUB.

When NOT to use XSLT

  • New JSON-based work — XSLT 1.0 cannot consume JSON. XSLT 3.0 can, but most developers will reach for jq / JavaScript / Python first.
  • Performance-critical — XSLT processors are not optimized for low-latency. Big documents over Saxon EE in streaming mode work, but JavaScript with a real DOM library is usually faster for one-off work.
  • Mobile apps — neither iOS nor Android ship XSLT. Bundling Saxon-JS is heavyweight.
  • Tasks with logic — XSLT is functional / template-matching. Complex conditional logic produces unreadable XSLT. Use a real programming language with XML library bindings.

When to reach for this tool

  • You have an XSLT stylesheet from a legacy system and want to test it against new input.
  • You inherited an XML transformation workflow and want to debug stylesheet behavior interactively.
  • You are learning XSLT (course, certification) and want a sandbox.
  • You are converting between XML formats (CDA → FHIR XML, RSS → custom XML) and need a transformation tool.

What this tool will not do

  • It will not run XSLT 2.0 or 3.0. Browser XSLT is 1.0 only. For 2.0/3.0, install Saxon locally.
  • It will not handle very large XML documents. Browsers cap at ~50-100MB; for multi-GB streaming, use Saxon streaming mode on a server.
  • It will not validate XML against schemas (XSD). XSLT and schema validation are separate concerns; use a separate XSD validator.
  • It will not convert XSLT 1.0 to modern code automatically. Migration to JavaScript, Python, or jq is a manual rewrite.

Frequently asked questions

Is XSLT still used in 2026?

Yes, in legacy contexts. New systems rarely choose XSLT — JSON tooling dominates. But many enterprise XML pipelines (banking, healthcare, government, B2B EDI) still run XSLT, and the cost of migrating them away outweighs the cost of maintaining them.

Why is XSLT so verbose?

XML-as-syntax. Every keyword (xsl:template, xsl:value-of, xsl:for-each) is an XML element. Each opening tag has a closing tag. Five lines of jq is fifty lines of XSLT 1.0. XSLT 3.0 has shortcuts but the core syntax remains XML-heavy.

Can I run XSLT 3.0 in the browser?

Yes — Saxon-JS (Saxonica's commercial product) runs XSLT 3.0 client-side. Open-source alternatives exist for 1.0 (libxslt port) but 2.0/3.0 in browser practically means Saxon-JS.

How do I debug XSLT?

Saxon, oXygen XML Editor, and XMLSpy have step-through debuggers. For ad-hoc testing, this tool plus xsl:message (prints to console) is enough for most cases.

Is XQuery similar to XSLT?

Same data model (XDM), same XPath, different programming style. XSLT is declarative template-matching; XQuery is more SQL-like (FLWOR — for, let, where, order by, return). Both can do similar things; XQuery feels more programmer-natural.

Can I generate JSON from XSLT?

In 3.0, yes — xsl:stream and json-to-xml support JSON input/output. In 1.0/2.0, you can emit JSON as a text-output document but cannot conveniently consume JSON.

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Published · Updated · E-Utils editorial team