XSLT Tester

About this tool

XSLT (Extensible Stylesheet Language Transformations) is a language for turning one XML document into another document — often HTML for display, sometimes a different XML shape, sometimes plain text. A stylesheet is itself an XML document made of templates: each template says "when you find something matching this pattern, output this." The engine walks your source XML, matches nodes against your templates, and builds the output as it goes.

This tool runs the transformation using the XSLTProcessor built into your browser — the same engine your browser would use if it encountered an XML document with an <?xml-stylesheet?> processing instruction pointing at an XSLT file. That means transformation happens entirely client-side, with no server involved, but it also means the tool inherits whatever XSLT version and feature set your specific browser ships. See Limitations below for exactly what that means in practice.

Output preview

If your stylesheet's output looks like HTML, a Preview tab appears alongside Raw so you can see it rendered rather than just as markup text. The preview renders inside a sandboxed <iframe> with scripting disabled, so any <script> tags your stylesheet happens to output will not execute — this tool never runs arbitrary code from your XML or XSLT, even in the preview.

How to use it

1. 01

   Paste, upload, or drop your XML and XSLT

   Each panel accepts a file drop or the Upload button, or you can paste directly.

2. 02

   Click "Run transformation"

   Or press Ctrl/Cmd + Enter anywhere in the tool.

3. 03

   Check the output

   Switch between Raw and Preview (when available) to see the result as text or rendered HTML.

4. 04

   Copy or download the result

   Copy to your clipboard or download the raw output as a file.

Common XSLT patterns

<xsl:for-each select="order">
  <tr>
    <td><xsl:value-of select="@id"/></td>
  </tr>
</xsl:for-each>

<xsl:value-of select="customer"/>
<xsl:value-of select="@id"/>

<xsl:if test="qty > 1">
  (multiple)
</xsl:if>

<xsl:choose>
  <xsl:when test="@price > 100">
    Expensive
  </xsl:when>
  <xsl:otherwise>
    Affordable
  </xsl:otherwise>
</xsl:choose>

Common use cases

Limitations

• XSLT 1.0 only. This tool uses your browser's built-in XSLTProcessor, and no major browser implements native XSLT 2.0 or 3.0 support. Features from later versions — like xsl:function, grouping with xsl:for-each-group, or the expanded XPath 2.0/3.0 function library — are not available here.
• Error messages come from the browser, and they're often minimal. Unlike a dedicated command-line XSLT processor (such as Saxon or xsltproc), browser XSLT engines frequently report only that a transformation failed, without a precise line number or a detailed description of which template or XPath expression caused it. This tool surfaces whatever the browser provides and adds guidance for the most common causes, but it can't manufacture diagnostic detail the browser itself doesn't return.
• Behavior can vary slightly by browser. Since the transformation runs on your browser's own engine, extremely edge-case stylesheets could theoretically behave slightly differently between browsers. Mainstream XSLT 1.0 features are consistently supported across current Chrome, Firefox, and Safari.
• xsl:output method="text" and other non-HTML output is supported, but very unusual output shapes (e.g. output that isn't well-formed XML and also isn't declared as text) may not serialize back to a string exactly the way a dedicated processor would.

Troubleshooting

• "Invalid XML" / "Invalid XSLT" — one of your two inputs isn't well-formed. Both XML and XSLT are XML documents, so both need valid tag nesting and closing. Use the XML Formatter & Validator if you need exact line/column detail.
• "Transformation failed" with no further detail — this is the browser XSLT engine's own limited error reporting, not something this tool is withholding. Common causes: no xsl:template matches your document's root, a namespace mismatch between your XML and your match/select patterns, or an XPath expression referencing an element that doesn't exist in your XML.
• Output is empty but no error appeared — this usually means your templates matched something, but produced no output for it (an empty xsl:template, or a select that matched zero nodes). Check that your XPath expressions actually match elements present in your XML.
• Preview tab doesn't appear — the Preview tab only shows up when the output looks like HTML. If your stylesheet outputs XML or plain text, check the Raw tab instead.
• Namespace-related mismatches — if your source XML declares a default namespace, your stylesheet's match and select patterns need to account for it (typically by declaring and using a matching namespace prefix in the stylesheet) or they won't match anything.

Frequently asked questions

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