XSL-FO and PDF generation pipelines

XSL-FO is a page description language driven by XSLT. It still produces the best paginated output, at the cost of a second transform and a heavier toolchain.

The two-stage pipeline

The usual shape is: source XML plus a stylesheet produce a formatting-object document, and a formatting-object processor turns that into PDF. The XSLT stage has no knowledge of pagination; the FO processor decides where pages break.

# Stage 1: XML to XSL-FO
xsltproc --output book.fo to-fo.xsl book.xml

# Stage 2: XSL-FO to PDF with Apache FOP
fop -fo book.fo -pdf book.pdf

# One command, two stages, for a build script
fop -xml book.xml -xsl to-fo.xsl -pdf book.pdf

<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
  <fo:layout-master-set>
    <fo:simple-page-master master-name="A4" page-height="297mm" page-width="210mm"
                           margin="20mm">
      <fo:region-body margin-bottom="15mm"/>
      <fo:region-after extent="10mm"/>
    </fo:simple-page-master>
  </fo:layout-master-set>

  <fo:page-sequence master-reference="A4">
    <fo:static-content flow-name="xsl-region-after">
      <fo:block text-align="center" font-size="8pt">
        Page <fo:page-number/> of <fo:page-number-citation ref-id="end"/>
      </fo:block>
    </fo:static-content>
    <fo:flow flow-name="xsl-region-body">
      <fo:block font-size="16pt" font-weight="bold" space-after="6mm">
        <xsl:value-of select="//title"/>
      </fo:block>
      <fo:block font-size="10pt" text-align="justify">
        <xsl:value-of select="//summary"/>
      </fo:block>
    </fo:flow>
  </fo:page-sequence>
</fo:root>

Engine	Licence	Strengths	Weaknesses
Apache FOP	Apache 2.0	Free, predictable, good for tables and long documents	No hyphenation by default, limited font handling
Antenna House	Commercial	Excellent typography and CJK support	Cost, per-server licensing
RenderX XEP	Commercial	Fast, mature, good SVG support	Cost
Prince XML	Commercial	Takes HTML plus CSS instead of FO	Different input model

💡

If you already control the markup, CSS paged media with a headless browser or Prince gets you a paginated PDF from HTML in one stage and is easier for a web developer to maintain. Choose XSL-FO when you need strict control over page geometry, running headers and multi-column flows.

FAQ

Do I have to write XSL-FO by hand?

No — the second stage is generated by XSLT, so you write templates that emit fo: elements. DocBook and DITA toolchains ship stylesheets that already do this.

Why is my font missing in the PDF?

FO engines do not use system fonts by default. FOP needs an explicit font configuration file mapping the family name to the font file, and the PDF must embed it for the glyphs to be present.

Output methods and real use cases Calling XSLT from Java, .NET and Python

Last refreshed 2026-09-18.

XSL-FO and PDF generation pipelines

The two-stage pipeline

FAQ

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