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Louise Arnold

Can you trust your load testing?

How to meet today’s complex ecommerce demands with confidence

Keeping up with the Joneses

As online shopping habits change and grow, ecommerce operators are having to respond and adapt more quickly, anticipating new developments and building ever-greater capacity to stay ahead of the curve. Only last week, catalogue giant Argos suffered some embarrassing – and, no doubt, eye-wateringly expensive – downtime on the first day of their Black Friday sales. This occurred only a few weeks after an earlier issue that resulted in a series of unfortunate customer experiences, including reports of order details being ‘lost’, despite money already having changed hands. The glitches didn’t last long – but it just goes to show that even a few hours’ disruption can result in huge losses, as well as an avalanche of adverse publicity as we approach the busiest shopping period of the year.

Most major retailers commit a significant slice of their annual resources to ensuring that shoppers can browse and buy in an effortless and increasingly personalised way – anywhere, anyhow and anytime. And yet, with sky-high expectations from savvy shoppers accessing online stores from a variety of devices, it can feel as if, far from staying one step ahead, some retailers are constantly playing catch-up.

Taking nothing for granted

Any ecommerce site needs to include comprehensive load testing to ensure it can manage peak traffic demands. There are different approaches to this, but to avoid high-profile failures now is the time to move on from more traditional metrics such as concurrent users, instead investing in more realistic testing based on the genuine shopping habits of your customers at peak times.

With the complexity delivered by today’s ecommerce sites, basing load testing on concurrent users is misleading. Take two different scenarios; firstly 10,000 concurrent users visiting your homepage which is fundamentally static and delivers mainly cached data or 10,000 concurrent users browsing, searching and checking out from your site. Although both scenarios represent the same level of concurrent users, the stress each scenario places on the backend systems is clearly very different. You may believe your site is prepared for your peak traffic but will it really be able to handle genuine traffic levels and real users performing activities across your site?

Understanding metrics such as the number of orders per hour your ecommerce platform can handle gives a much more accurate and reliable indication of the true ability to handle peak traffic and an idea of the size of your online shop. To put this into context here are the top level results of a recent load test we recently carried out for a major high-street retailer’s ecommerce site.


Not all shoppers take one idealised journey so why should your load testing?

By performing more realistic load-testing, it’s possible not only to gain important insights about how customers’ behaviour impacts particular areas of your web provision but also to fully assess whether your site can handle predicted traffic over the busiest periods, with the aim of avoiding the financial and PR fallout from a major public meltdown. Load testing protocols need to be based on real user traffic and follow realistic sequences of events; online customer journeys and test a mix of those journeys.

To protect your business and your brand load testing needs to reflect the increasing complexity and sophistication that ecommerce platforms now deliver.


Load testing now needs to simulate users accessing ecommerce sites via mobile and desktop devices, make selections from page content along the journey and replicate ‘drop-off’ ratios. As in real life, some shopping carts are abandoned part way through the journey, while others go through to checkout.

This way, tens of thousands of journeys can be initiated and scaled up to or even beyond anticipated peak traffic levels. It’s the only way to ensure your shoppers will have a smooth passage through your site and can make their purchases without hindrance.

Tips for a smoother ride

If you’re not sure how your site will perform under pressure, there are a few things you can do to tip the scales in your favour:

  1. Implement a third-party queuing system; it’ll keep people off the site and could prevent a meltdown.

  2. Stagger marketing and promotional activities to avoid creating spikes in demand.

  3. Switch off any unnecessary functions.

  4. Have your site load tested regularly.

  5. Run 24/7 monitoring to stay on top of issues as they arise.

If you’d like more information about how taking a more realistic approach to load testing could help protect your revenue and improve your customer experience, download our Best Practice eBook here.

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