The three things to keep in mind as you prepare for peak

Peak traffic this Black Friday and holiday shopping season is going to look very different from years past. Deloitte estimates that ecommerce holiday sales will surge by 25% to 35% this year to between $182 and $196 billion. And with the influx of new shoppers, the typical buyer profile might change as well.

That means your ecommerce site needs to be prepared both for peak traffic as well as the different ways people may choose to shop — but it’s not as hard as you might think. A good game plan should include the following three best practices.

Know your applications’ limits

The first step in planning for peak is getting an understanding of where, how, and why your applications might fail. For example, get a grasp on what geographic regions will become your hot spots, your key markets, and your emerging markets. Make sure you know what kind of devices will be popular and ensure you can support them.

Because many people are turning away from shopping in the physical world, new customers might be different from the ones you already know. They may buy a greater variety of products, they may be unaccustomed to shopping online, they may not limit their shopping just to publicized deals. Try to anticipate the user experience your customers might encounter and optimize it for all. 

Choose a modern CDN to help you

To deliver the best experience to your customers, leverage third-party experience in the form of peer examples, forums, and your vendors. 

The right CDN can be vital. Look for one that’s been designed to meet the needs of today’s ecommerce companies by delivering content faster and letting you personalize the shopping experience. Your CDN should be able to cache frequently changing items and keep more in cache at the edge, closer to your customers, including dynamic content and API responses. The best CDNs can also invalidate in 150 milliseconds or less, on average, which is particularly useful when a massive number of simultaneous users interact with your site. 

To better meet demand, your CDN should be able to deliver content based on visitors’ geo-location, device type, or any other aspect of their request, by computing logic at the edge. The right CDN makes A/B testing easier, so you can  learn about buyer proclivities in different regions or on different devices and immediately optimize for those. Ideally, the CDN shouldn’t use third-party tags in your HTML, which requires sending requests back to origin. Eliminating those tags makes your online store run faster and improves the overall user experience. 

Make sure your applications can scale

Once you’ve gained an understanding of your applications’ limits and leveraged third-party assistance, it’s time to test, test, and test again to make sure your applications can scale. Throw both real traffic and test traffic at them, and have performance goals in mind (page loading time, time-to-first-byte, time-to-first-interaction, error rate), then test and fine-tune your CDN and site design until you reach them.

Load testing should be a priority. Many technology stacks have bottlenecks that are only exposed during times of high traffic. When the number of requests exceeds the available computing power, a “thundering herd” problem can be created, causing availability issues and performance degradation. Other issues can result in a slow customer experience, or worse, a full outage.  

In general, avoid load testing through your CDN. CDNs have been designed to take on a lot of traffic, so testing through them won’t uncover your bottlenecks. Instead, look for gaps in delivery for things that don’t scale well, such as your database, applications, and connections to the origin. Test the fail points. Discover where the gaps are and how deep they are. 

When testing, keep in mind that adding a large amount of traffic gradually may not uncover issues, because your site may be able to work properly when the load is steadily increased. Sudden spikes are harder to manage because internal management systems can’t compensate quickly enough. Testing sudden increases in load as well as gradual increases will highlight where your application’s weak spots are.

Test each individual page in the shopping flow. Generally, landing pages are somewhat static, so might be able to withstand traffic spikes. But shopping baskets and checkout use more back-office resources, like databases, so are more of a potential bottleneck, which we all know impacts user experience and increases cart abandonment.

What’s next?

If you do all this, your site should be better able to withstand whatever traffic is coming its way this shopping season. And once code freeze hits, it’s time to start thinking about next year — and maybe time to get a demo of Fastly and see how our edge cloud platform can help you prepare for traffic spikes year round.