Zilla Slab

Zilla Slab font preview
Replaces: Clarendon (80%) | OFL-1.1 | Updated: Jan 2026

About Zilla Slab

Classification
serif
Weights
300, 400, 500, 600, 700
Features
Italics
SIL Open Font License 1.1
Free to use, modify, and distribute. Can be used commercially without attribution.
Get Zilla Slab Free ↗

Zilla Slab is a slab serif typeface designed by Typotheque for Mozilla's brand identity. Released in 2017, it combines the strength of traditional slab serifs with contemporary refinement, serving as Mozilla's primary headline typeface and demonstrating how open-source principles can extend to brand typography.

History and Design

Typotheque designed Zilla Slab as part of Mozilla's comprehensive rebrand, which emphasized openness and inclusivity. The design brief called for a typeface that would feel strong and trustworthy while remaining approachable—qualities central to Mozilla's mission.

The result features bracketed slab serifs in the Clarendon tradition, with carefully refined proportions optimized for digital display. The design balances authority with warmth, making it suitable for both assertive headlines and friendly communications.

Why Zilla Slab Excels

Zilla Slab demonstrates how slab serifs can feel contemporary rather than nostalgic. Its refined details and optimized spacing create excellent screen readability without sacrificing the distinctive presence that makes slab serifs effective for branding and headlines.

Technical Features

  • Five weights: Light through Bold for flexible hierarchy
  • True italics: Distinct italic designs, not obliques
  • Web optimized: Designed for screen rendering
  • Extended Latin: Comprehensive character support
  • Open source: Available under OFL for any use

Best Use Cases

Zilla Slab excels in:

  • Tech branding: Modern, trustworthy identity
  • Headlines and titles: Strong presence with readability
  • Digital products: Interface elements and marketing
  • Open source projects: Values-aligned typography choice

Usage Tips

Zilla Slab shines in headlines from 24px upward, where its refined details become visible. Medium and SemiBold weights provide strong presence without heaviness. Pair with Mozilla's Zilla Sans (if using the full Mozilla identity) or alternatives like Open Sans, Lato, or Source Sans Pro. The bracketed serifs require adequate size to render clearly—avoid using below 16px.

Alternative For (2)

Zilla Slab is a free alternative to the following premium fonts:

[Linotype] · serif

Mozilla's slab serif with contemporary refinement and strong branding presence

View all alternatives →
#2 Sentinel 72%
[Hoefler&Co] · serif

Contemporary slab serif with strong presence and digital optimization

View all alternatives →

How to Use Zilla Slab

Copy these code snippets to quickly add Zilla Slab to your project.

CSS Import

@import url('https://fonts.googleapis.com/css2?family=Zilla+Slab:wght@300;400;500;600;700&display=swap');

HTML Link Tags

<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link href="https://fonts.googleapis.com/css2?family=Zilla+Slab:wght@300;400;500;600;700&display=swap" rel="stylesheet">

Tailwind CSS

// tailwind.config.js
module.exports = {
  theme: {
    extend: {
      fontFamily: {
        'zilla-slab': ['"Zilla Slab"', 'sans-serif'],
      },
    },
  },
}

// Usage in HTML:
// <p class="font-zilla-slab">Your text here</p>

React / Next.js

// Using next/font (Next.js 13+)
import { Zilla_Slab } from 'next/font/google';

const zilla_slab = Zilla_Slab({
  subsets: ['latin'],
  weight: ['300', '400', '500', '600', '700'],
});

export default function Component() {
  return (
    <p className={zilla_slab.className}>
      Your text here
    </p>
  );
}

// Or using inline styles with Google Fonts link:
// <p style={{ fontFamily: '"Zilla Slab"' }}>Your text</p>