How Bloomberg sped up its sites to boost pageviews per visit by 15 percent

More than six months of data show that page-load time is down 40 to 50 percent on average across devices. (The company wouldn’t provide parameters, saying that load times are based on various factors and every company measures speed differently.) The speed boost contributed to an increase in viewability from 80 percent to 84 percent, pageviews per session increased from 3.6 to 4.2 and impressions per session are up 10 percent, said Dan Hallac, head of digital web product at Bloomberg. Bloomberg’s mobile load time still “needs work,” according to Google’s speed test tool, but that’s an improvement from the “poor” rating it received in October.

A big reason why Javelin led to a speed improvement is because it moved Bloomberg onto HTTP/2 protocol. Because HTTP/2 transfers data as binary code rather than as text (like original HTTP protocol does), it compresses information for ad servers. This speeds up page loads, which makes the new protocol particularly enticing for mobile usage. Bloomberg’s digital media properties had 32 million unique visitors in May, with two-thirds of this traffic coming from mobile, according to comScore.

The quest to decrease load times isn’t unique to Bloomberg. Publishers like Vice, Meredith and HuffPost have recently invested in their tech infrastructures to increase their page speeds. The industry’s sensitivity toward ad blocking and slow mobile connections has also led publishers to adopt fast-loading article features like Google Accelerated Mobile Pages and Facebook Instant Articles, even though that involves ceding webpage control over to powerful platforms. Bloomberg uses AMP and Apple News, but not IA, according to a company spokesperson.

“The biggest win is something people don’t see,” said Hallac, who denied Javelin was purely a speed play for the publisher. “It the underlying tech for it.”

Javelin’s code uses a “continuous integration” setup, which means it allows web developers to make adjustments on the fly and update websites whenever a developer wants to make a single change. Previously, multiple updates would simultaneously come out in a package. On a typical day, Bloomberg now makes about four individual adjustments across its web properties. Back in September, it released just one pack of updates every few days.

By making changes individually rather than in a pack, developers can more easily isolate and fix problem areas, said Pavan Kulkarni, an engineering group manager at Bloomberg. For example, if Bloomberg released a pack of updates in which it simultaneously added social media share buttons, third-party verification tags and content-recommendation widgets to its webpage, and the website began to slow down, it would be difficult to determine which variable caused the drag. By making these adjustments individually, web developers can spot the specific problem more quickly, which frees them up to work on other projects rather than having to A/B test all the other variables that might be causing latency.

To build and launch Javelin, Bloomberg deployed four developers, a web designer and a product person to work on the project for two to three months, Hallac said. After the launch, that team worked on the project for another couple of months as it rolled out across Bloomberg’s verticals.

While the changes to Bloomberg’s back-end setup have helped the publisher speed up its sites to drive more impressions per visit, many publishers don’t have enough tech talent to devote to these projects. Only 15 percent of websites have made the switch to HTTP/2, according to web analytics firm W3Techs, and some publishers still rely on outdated Flash technology to fill their video inventory.