Vox’s sites have become synonymous with forward-thinking design and splashy article presentations, but it has paid less attention to how those sites actually perform. This year, though, its engineers started to look more closely at the numbers. What they saw wasn’t pretty. Vox’s seven sites took an average of more than 23 seconds to load, far longer than competing publishers such as Mashable and The Huffington Post. Vox’s engineers had declared “performance bankruptcy.”
A few months later, the situation has improved. Vox has managed to cut its sites’ average page load time to around 11.5 seconds, thanks to a combination of smaller and larger tweaks. The site even hired a pair of “performance engineers” to focus on the problem full-time. It also plans to hire a third, to be assigned to the advertising staff.
“We’d been aware for a while that as we were building these new sites, we were accruing plenty of technical and performance debt that we had to go back and fix,” said Dan Chilton, Vox Media’s front-end engineering director. “We were finding it hard to go back catch up on the issues we had left unsolved.”
Vox started with the low-hanging fruit that would yield the biggest improvements, said Chilton. Vox’s engineers streamlined how Vox’s sites handled their fonts, many of which were redundant and delivered inconsistently. Vox also implemented Google’s WebP image format, which promises to cut image size by up to 34 percent while not sacrificing quality. That tweak alone cut 500 milliseconds off page load time.