\begin{article}

XeLaTeX vs pdfLaTeX: Which Engine Should You Use?

A practical comparison of XeLaTeX and pdfLaTeX — covering Unicode support, custom fonts, compilation speed, and when to choose each engine.

Jun 7, 2026·4 min read·

enginesxelatexpdflatex

Choosing the wrong LaTeX engine is one of the most common sources of compilation errors. Both pdflatex and xelatex produce PDFs, but they work differently under the hood — and the difference matters for your document.

The Short Answer#

Use pdflatex unless you need custom fonts or non-Latin scripts. Then use xelatex.

pdfLaTeX#

pdflatex is the default engine and the fastest of the four FormatEx supports. It has been the standard for decades and works with virtually every package on CTAN.

curl -X POST https://api.formatex.io/api/v1/compile \
  -H "X-API-Key: $KEY" \
  -d '{"content":"...","engine":"pdflatex"}'

What it does well:

• Fastest compilation time
• Widest package compatibility
• Best supported by journals and publishers
• Available on the free plan

Limitations:

• Encoding handled via inputenc and fontenc packages
• Limited to fonts converted to Type 1 or TrueType formats
• Non-Latin scripts require workarounds

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\begin{document}
Standard document — pdflatex handles this perfectly.
\end{document}

XeLaTeX#

xelatex was built to address pdfLaTeX's font limitations. It uses the Unicode standard natively and can load any OpenType or TrueType font installed on the system — or bundled with your project. When using all four LaTeX engines via the API, XeLaTeX is the go-to choice for font-heavy documents.

\documentclass{article}
\usepackage{fontspec}
\setmainfont{TeX Gyre Termes}
\begin{document}
This uses a custom OpenType font directly.
\end{document}

What it does well:

• Native Unicode input — no inputenc needed
• Load any system or OpenType font with fontspec
• Right-to-left languages (Arabic, Hebrew) via bidi
• Better for multilingual documents

Limitations:

• Slower than pdflatex
• Some older packages (especially font-related) are incompatible
• Requires Pro plan or above on FormaTeX

Side-by-side Comparison#

Font Loading in XeLaTeX#

The fontspec package is the key difference. You can reference fonts by name:

\usepackage{fontspec}
\setmainfont{Georgia}
\setsansfont{Helvetica Neue}
\setmonofont{JetBrains Mono}

Or by file path when bundling fonts with your project:

\setmainfont{CustomFont}[
  Path = ./fonts/,
  Extension = .otf,
  UprightFont = *-Regular,
  BoldFont = *-Bold,
  ItalicFont = *-Italic
]

Which to Pick via the API#

When building LaTeX PDF generation in Node.js and TypeScript, selecting the right engine at runtime keeps your code portable across document types:

const engine = needsCustomFonts || hasNonLatinScript
  ? "xelatex"
  : "pdflatex";

const response = await fetch("https://api.formatex.io/api/v1/compile", {
  method: "POST",
  headers: { "X-API-Key": process.env.FORMATEX_KEY! },
  body: JSON.stringify({ content: latexSource, engine }),
});

What About LuaLaTeX?#

LuaLaTeX via API shares XeLaTeX's Unicode and font capabilities but adds a full Lua scripting environment. If you don't need scripting, XeLaTeX compiles faster. See the complete guide to LaTeX engines for a full four-way comparison covering pdfLaTeX, XeLaTeX, LuaLaTeX, and latexmk.

Related Articles#

• The Complete Guide to LaTeX Engines — Deep dive into all four engines (pdfLaTeX, XeLaTeX, LuaLaTeX, latexmk) with guidance on when to use each
• Using All Four LaTeX Engines via the API — Practical code examples for switching engines in REST API requests
• LuaLaTeX via API: Programmable PDFs — How LuaLaTeX extends XeLaTeX's font support with a full Lua scripting layer
• LaTeX PDF Generation in Node.js and TypeScript — Full TypeScript client showing engine selection with error handling
• Getting Started with FormaTeX — First API key, first compilation, and how to specify your engine of choice

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