The holiday season, the busiest time for many retailers, presents a number of site performance challenges for online storefronts big and small.

Massive holiday traffic usually causes some retail sites to stumble during the period of Thanksgiving through Cyber Monday, also known as the Cyber 5.

The number of retail site crashes increased slightly this year, according to Catchpoint Systems Inc., which monitors website performance. “This year, we saw six major performance degradations, compared to five major degradations in 2016 and a total of seven in 2015,” says Catchpoint CEO Mehdi Daoudi. “The major difference between this year’s problems and previous years was that they seemed to occur earlier, starting on Thanksgiving, and were shorter in duration.”

One of the major outages was prompted by a Cyber Monday deal. J. Crew Group Inc., No. 50 in the Internet Retailer 2017 Top 500, offered 40% off everything plus an additional 10% off sitewide. That led to a surge in traffic that brought the site down around 10 a.m. Eastern on Cyber Monday (Nov. 27), according to a spokeswoman. The retailer extended the sale until midnight, an extra 12 hours, due to the downtime.

While was down, shoppers received a message stating that J. Crew was “experiencing more traffic than usual.” The page offered a phone number to call to place an order. Shoppers took to Twitter to complain about the outage, and J. Crew announced the extension of Cyber Monday sale on the social media site at 2 p.m. Eastern.

When H&M (No. 409) went down for an hour on Thanksgiving Day (Nov. 23) due to heavy traffic, the apparel retailer displayed a splash screen explaining that the launch of Black Friday deals led to the “fashionable waiting time” for the site to return. It also included a button to enable users to reload the page. The outage hit Thursday evening, but the site was back online early Friday morning and intermittently on Saturday morning.


While increased traffic appears to be behind the crashes at sites like J. Crew and H&M, Catchpoint says technical issues like malfunctioning plug-ins and integrations plagued a number of slow-loading sites., owned by Gap Inc. (No. 24), had load times approaching 30 seconds, according to Catchpoint, which pointed to a faulty Snapchat integration as the cause of the slowdown. A Gap spokeswoman said they didn’t see a slowdown on the site.

Despite some glitches, retail websites were faster overall during the Cyber 5.

Performance management software company Dynatrace found that the average response time for U.S. retail sites across mobile and desktop from Thanksgiving through Cyber Monday was 7.36 seconds, while response times for the same weekend in 2016 averaged 10.7 seconds. However, success rates, a measure of the ability to access a site, decreased slightly to 98.4% this year compared with 99.4% over the Cyber 5 in 2016.

Complex and distributed environments, including the cloud and content delivery networks, were the main culprits for site failures, says David Jones, sales engineering director at website performance management firm Dynatrace. “Our results show that moving to the cloud has industry benefits for improving response times, but adding that complexity is impacting success rates,” he says.


For larger retailers, keeping site infrastructure in-house resulted in better performance over the holiday weekend. The 10 best-performing retail sites on Black Friday averaged a 1.3-second load time, according to web performance testing company Apica‘s analysis of 100 U.S. retail sites. Marketing manager Whitney Donaldson says these sites performed well because they didn’t place calls for data to many other sites.

“To load the entire Apple store home page, your browser has to connect to only four domains—all hosted by Apple,” she says. “To load the Gap website, your browser has to connect to 74, which are hosted by a number of different companies in different locations.” Apple is No. 2 in the Top 500.

Limiting calls to other web-based services isn’t always feasible, particularly for smaller retailers without the resources of a company the size of Apple. Many e-retailers rely on software they connect to via the internet for such services as site search, product recommendations, social sharing and video playback.

Duke Tung, managing director at skincare retailer EDCskincare, says most of his vendors are fully staffed on the holiday weekend to make sure sites run smoothly. The retailer uses many third-party tools, including for its shopping cart and its newsletter service. EDCskincare didn’t experience downtime over the holiday weekend, despite heavier Black Friday traffic compared with last year.

Greg Hellings, director of systems engineering at site search vendor SearchSpring, says the company is prepared to scale up servers for the holidays.



“To ramp up for Black Friday/Cyber Monday, we bring on a lot of extra server infrastructure to handle the increased load,” Hellings says. “We do a lot of performance testing several weeks out, and actually so do our customers, so we bring on that extra infrastructure before they start testing.” He says the company tests its infrastructure with far heavier traffic volumes than it expects to see during peak periods.

Mobile performance is an especially important focus for retailers. On Black Friday, mobile accounted for 36.9% of total online revenue, a new record, according to data from Adobe Systems Inc. The company also says mobile accounted for 30.3% of Cyber Monday sales.

Catchpoint found that the best-performing mobile retail sites had average load times of under one second during the holiday weekend this year, faster than the top-performing desktop sites. Last year, none of Catchpoint’s tracked sites, mobile or desktop, averaged under a second.

“On mobile, we are seeing the performance of the top performers continuing to improve,” Daoudi says. “This year’s mobile site index shows that the top performers are increasingly getting under the one-second mark, raising the bar for all retailers.”


However, sub-one-second loads are still elusive during peak times of the Cyber 5. On Cyber Monday, the fastest mobile page was Amazon Inc. (No. 1 in the Top 500), which took 1.3 seconds to load, nearly four times faster than its desktop site (4.01 seconds).  However, mobile performance quickly dropped off, with the fifth-fastest mobile site, Costco Wholesale Corp. (No. 9), taking 3.49 seconds to load its mobile page.

However, no major problems this year were tied specifically to retailers’ mobile sites. Last year, two of the five problems Catchpoint reported were due to mobile traffic, while Target Corp. (No. 20) had major mobile site performance issues in 2015.