xz/fonts is a free and open source service for delivering font families to websites using CSS. Typically, web developers use custom fonts on their websites using one of two methods:
Hosting font files on the same server as the website
Using a central font service, such as Google Fonts or Adobe Typekit
xz/fonts, by comparison:
serves font files through jsDelivr's global content delivery network
is open source and only serves open souce fonts
We're on GitHub at xz/fonts.