katex

KaTeX is a fast, lightweight math typesetting library for the web that renders LaTeX-style mathematics in the browser. It is designed to produce high-quality mathematical output with minimal JavaScript and aims to be a performance-focused alternative to older engines such as MathJax. KaTeX is an open-source project that originated with Khan Academy and is maintained by a community of contributors on GitHub. It is released under the MIT License.

KaTeX supports a substantial subset of LaTeX math syntax, including fractions, roots, superscripts and subscripts, integrals and sums, matrices, accents, and many operators. It renders directly to HTML and CSS, producing accessible markup without requiring a full TeX engine. The library emphasizes consistent rendering across browsers and environments and can be used in client-side rendering as well as server-side contexts via the Node.js package katex.

Usage typically involves including the KaTeX CSS and JavaScript in a web page and calling render or renderToString to produce HTML from a TeX expression. KaTeX also offers an optional auto-render extension that can automatically typeset math within page content, and a server-side rendering pathway for generating HTML on the server. The API supports customization through options such as macros, error handling, and a strict mode.

In comparison with MathJax, KaTeX prioritizes speed, smaller footprint, and deterministic rendering over breadth of TeX package support. It remains a popular choice for websites and applications that require fast, reliable display of mathematical formulae.