Zach’s ugly mug (his face)

Zach Leatherman

The Font Loading Checklist

August 29, 2018 #16 Popular 23,981 Views

When I look back at the last four years that I’ve spent learning everything I could about web fonts and how web fonts load, I can distill it all down to a small checklist of ideals that I continue to chase. Our goal as web developers is to maximize the experience and raise user expectations to the level of what the web is capable of delivering, but also to manage our performance budgets to ensure that we are fulfilling the promise of the web—it’s ubiquity. This checklist should help you deliver on those two often competing ideals.

The Font Loading Checklist

(Start a Web Font load)

Web fonts don’t start downloading until they’re found to be used in content, so it’s often late in the page load. We need to tell the browser to start downloading our high priority web fonts sooner.

(Behavior while a Web Font is loading)

This means absolutely no invisible text. This is known as the flash of invisible text, or FOIT. We can use flash of unstyled text (FOUT) strategies to prioritize system fonts during web font load.

(Reduce Web Font load time)

Guess what: Smaller file downloads finish sooner.

  • Strategy: Use WOFF2 formats (compression built in)
  • Strategy: Subset your fonts, if language and licensing requirements allow.

Check out Glyphhanger to help with both of these strategies.

(Behavior after a Web Font has loaded)

Each independent @font-face block has its own loading life-cycle. Its own FOIT, its own FOUT, its own repaint and reflow. When using two or more web fonts for a single family, its important to group the repaints together to reduce reflow of text on your page.

Zach’s ugly mug (his face)

Zach is a builder for the web with IndieWeb Avatar for https://www.netlify.comNetlify. He created the IndieWeb Avatar for https://www.11ty.devEleventy site generator and is still fixated on web fonts. His public speaking résumé includes talks in eight different countries at events like Jamstack Conf, Beyond Tellerrand, Smashing Conference, CSSConf, and The White House. He is an emeritus of Filament Group, NEJS CONF, and still helps out with nebraskajs’s AvatarNebraskaJS. Read more about Zach »

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4 Replies
  1. Zach Leatherman

    @zachleat

    Yay! I’m really glad to see someone picking up the torch there 🏆

  2. Lee Robinson

    @leeerob

    Thank you for your posts on web fonts 🙏 They really helped me learn and understand all the tradeoffs.

  3. Zach Leatherman (away)

    @zachleat

    (sounds good!)

  4. Let me do what I do best here: Make scary things approachable and friendly :) @zachleat Ok with viewing a preview (when I'm done) before I release the post to the public?

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