With the recent Black Friday and Cyber Monday hype many online stores were put to a very unique test. Any business that had a special offer was likely to be inundated with visitors trying to grab themselves a bargain.

Websites giants like Amazon, John Lewis and Apple are used to this huge amount of traffic, but some smaller sites may not be quite as used to it and as a result faced a slow down or maybe even crashed altogether! Here’s hoping your site was not among those affected but have you ever tested your site under abnormal stress?

Think of a scenario where your website averages 100 visits per day. Maybe you then go to launch a new product or service along with press releases, social media and email campaigns, and maybe a conference or workshop as well.

If your website were to crumble under the pressure then that could be a lot of potential clients left out in the cold and possibly a damaged reputation. You could be getting thousands or tens of thousands of visitors over the coming days.

That is a worst case scenario but do you want to take the risk? I’m guessing not, but have you tested your website against many times your usual traffic? Can the code and hardware behind your website cope? Can your email system cope with the influx or contact enquiries or order notifications? Are you and your staff prepared for the sudden surge?

Piling on the pressure

Scenarios like this are the very reason why you should stress test your website, especially in advance of a big influx of traffic.

There are numerous ways to stress test your site but what can you do to prevent issues occurring?

Know the limits

Stress testing is the best way to find the limits of your website.

Intentionally pushing your site to its limits will give you an idea of where the bottlenecks are and what improvements can be made. This will highlight various areas that can be looked at to improve speed and reliability and also give you an idea of where your website starts to struggle.


Browsers and servers both have a functionality in them called a cache. In short this is a space where they can store data to be re-used later.

For example when you visit a website it is likely to download some stylesheets, JavaScript files and images etc. When you revisit the same website these resources are already there to save you having to download it again. This saves time in loading the website and saves work for the server which frees up resources for other users. You will need to check how your website uses these caches and alter the settings if need be.

Content Delivery Networks (CDN)

A CDN is the method of spreading some of your websites components around for example images, stylesheets etc.

This utilises multiple servers to host various parts of your website but if one server can handle the request quicker than another server, either due to load or even geographical location, then the best server will be used.

This spreads the load across multiple servers instead of focussing on just one, allowing more users to use the resources simultaneously.

Optimise the page

This may seem like an obvious one, but it is one that is easily overlooked.

This step requires looking at the code of the website as a whole and also each individual page and see which parts take longer than they should for example the query to get stock levels etc. Are the pages being slowed by unnecessary adverts loading or images that have not been optimised?

All of these things whilst maybe only saving a few milliseconds can add up very quickly, even more so when spread across hundreds or thousands of users. Sometimes optimising code is harder than it sounds, especially on packages such as WordPress and other website builders.

Compromise on things other than speed

No matter how much you optimise your site you will find a limit eventually.

If you leave the site running slowly then you will notice people leaving. We talked more about the impact this can have in a previous blog post Do you have a second? but there are other ways around this. For example if your site reaches a critical load time, the page can automatically drop various un-needed sections such as advert banners or promo boxes. Things that are not key to selling or informing users.

For the most part we are talking about huge limits before finding any problems if your website is smooth and on reliable hosting but can you afford to be complacent before a big launch or event? It is worth testing and making sure you can cope because that is easier to rectify than lost custom and reputation.

Published: 30th Nov 2017

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