According to: https://developers.google.com/speed/pagespeed/insights/?url=http%3A%2F%2Fpub.dartlang.org%2Fpackages%2Fhttp We have work to: "Ensure text remains visible during webfont load". "Leverage the font-display CSS feature to ensure text is user-visible while webfonts are loading" See: https://developers.google.com/web/updates/2016/02/font-display