Font loading, explained without the jargon

We end up explaining this on discovery calls often enough that it deserved writing down. Here is font loading without the vocabulary that usually surrounds it.

Speed is a feature people notice only in its absence, and then they leave rather than complain. If it only works because one person remembers to do something, it does not work yet.

The short version

Custom fonts commonly block the first paint. There is a version of this that is over-engineered, and it is worth avoiding. The version that survives contact with a real deadline is the simple one.

Why people complicate it

Most of the confusion comes from tooling rather than from the idea itself. That sounds obvious written down. It is still the thing most often skipped.

Self-hosting removes a third-party round trip. That sounds obvious written down. It is still the thing most often skipped. If it only works because one person remembers to do something, it does not work yet.

Where to go from here

A sensible fallback prevents invisible text. The teams that handle this well are rarely the ones with the biggest budgets. Check it against what you would want a competitor's site to get wrong.

In practice

Performance work is mostly subtraction, which makes it unpopular and effective. Three things worth confirming about font loading before you move on:

• Someone can say what the current setup is without going to look
• Custom fonts commonly block the first paint — and you know whether that is true here
• There is a way to tell whether the last change to this helped

Pick the one that would hurt most if it failed, and start there.