How did Britain's top retail sites cope with Black Friday?
So, Black Friday came and went. And, for the most part, Britain’s online retailers can breathe a collective sigh of relief. Despite surges in visitor numbers for many of the big players, meticulous capacity planning and traffic management appear to have paid off, and most have emerged with revenue and reputation unscathed. We’re pleased to have helped a number of them with load testing and performance optimisation in preparation for the big day.
A look at our monitoring data reveals reassuringly consistent performance for the vast majority of our top retailers. The pattern in the graph below is typical:
Consistent load times for one major retail home page, 23–27 November 2016
That’s not to say that it was all plain sailing for everyone. A few retailers did see an impact on performance during Black Friday. For example, the following site saw a higher number of slow tests over the course of the day. These were almost all due to a slow response from an instant chat facility. So while the page itself was able to load and display without any issues, visitors looking to speak with sales or customer services representatives might have been frustrated.
A number of slow responses on Black Friday for this retailer, as a script required for an instant chat service was delayed (results shown for the period –27 November)
Another retailer saw a more noticeable slowdown, although this time third-party tags were the culprit. These wouldn’t have blocked first-party content, so the impact of the user experience would have been minimal. However, it does illustrate the point that while retailers might have prepared well for Black Friday, they had no control over the performance of third-party services, some of which appear to have fared less well. In this case, it appeared to be advertising platforms, but it’s also important to keep track of the performance of other services, such as analytics, to ensure that data capture, as well as advertising revenue, is optimised (one reason why it helps to audit third-party tags regularly).
Third-party tags were responsible for slow tests on this retailer’s home page
In previous years we’ve seen retailers create problems for themselves with oversized promotional Black Friday imagery, bloating page weight and holding back load times. However, this doesn’t seem to have been as much of an issue this time around.
In fact, at least one retailer managed to cut page weight over the busy period, removing a video and reducing the volume of imagery – and seeing a corresponding fall in load times as a result.
This retailer delivered a lighter, faster home page on Black Friday (load times are indicated by the green bars, page size by the grey area)
Over the past few years, we’ve seen websites in general – and retail sites in particular – getting bigger and slower. So the fact that most of them have proved resilient enough to deliver consistent performance during the busiest time of the year is a welcome piece of good web performance news. It suggests that good planning and testing are paying off, with different areas of the business (ecommerce, marketing, IT) working together to ensure that customers can continue to buy their goods and services online.
Published date:  01 December 2016
Written by:  Alex Painter