How Dunelm replatformed its e-commerce to speed up digital delivery

Dunelm is one of the UK's largest home furnishings retailers, with 169 superstores, three high street stores and 100 coffee shops across Britain. The company, which is listed on the London Stock Exchange, brought in revenues of £1.1bn in 2019.

Like many retailers, Dunelm has built up its e-commerce presence over the years. It had initially used WebSphere, an off-the-shelf e-commerce platform, that enabled the business to accelerate its online presence. In addition, the company had a Content Delivery Network (CDN) from Akamai's Instart Logic.

However, Tom Hayman, head of platform at Dunelm explained that despite both the platform and the CDN being a success until 2017, the legacy tech was not fit-for-purpose for the future. He said:

It was difficult to scale and make changes quickly, and we couldn't add new features to the platform. To make a change we would do one or two releases per month, and it was always a very difficult process.

Over the years, Dunelm did not have the expertise in-house to build a platform themselves. That changed when it acquired e-commerce company Worldstores in 2016 for £8.5m, as many of its team had the required knowledge.

Along with the experts brought in from Worldstores, Dunelm hired a number of specialists, and this enabled the company to embark on an 18-month journey to rebuild the platform which underpins Dunelm.com. The aim was to be able to release features and improvements to the website often, consistently, and securely for its customers.

The company predominantly built the new platform on serverless technologies, replacing the company's on-premises product with a cloud-based architecture on Amazon Web Services. This made the platform a lot faster, according to Hayman, who said that the website search function has a much quicker load time as a result.

The replatforming was completed in October 2019, and six months later the company then decided to change its CDN to align with its new infrastructure-as-a-code strategy. Dunelm selected edge cloud provider Fastly's programmable CDN after testing the software out and finding speed improvements on a selected number of its web pages.

On implementation of Fastly, Hayman said:

We built a lot of the configuration into our infrastructure-as-code choice which is Terraform. So, we did a lot of the work upfront, but the platform team had to learn about Fastly, and it had to be tested in pre-production environments and integrated there first to get an understanding of the product.

One of the things we could test quite easily on Dunelm.com was on a certain percentage of traffic through Fastly and see where there were errors and problems and fix those errors. We could send 10% for our traffic to Fastly, and we could then fix problems and roll that 10% back down to 0%.

Once the product was completely implemented, Dunelm engaged with Fastly to get some more training to fill in any knowledge gaps. Hayman says that the platform team is now confident with the platform and the integration of Fastly.

Benefitting from a new platform and CDN

Since replatforming and installing Fastly, the team can make between 40 and 50 releases per week and this can lead to improvements to basket, checkout, search, or product pages. Hayman says that it is also much easier to help customers find products online.

Crucially, this speed means that engineers are afforded greater flexibility, meaning they can make strategic decisions swiftly. Fastly is also being used to help secure the platform as it serves as an extension of Dunelm's network. Hayman explained:

We integrated all of our APIs and microservices with Fastly's web application firewall to help us understand the threats and attacks on our platform. We've also integrated this with a monitoring solution, so we have a lot more visibility than we did on our previous CDN.

Overall, Hayman suggested it was difficult to work out return-on-investment (ROI) for the project as there are a lot of different factors that can influence conversion.

However, he said:

We've done a lot of load testing on the site, and we continue to do so, and we can basically take double the amount of traffic that we could during the peak period of Christmas.

Purging Dunelm's cache previously took 15 minutes to one hour. With Fastly, it now takes less than half a second. The retailer has also seen a 900% increase in page load speed, and a 23% increase in basket add.

All of these improvements have proved crucial during the pandemic as people turned to online shopping, as retailers were initially closed during nationwide lockdowns.

Hayman said:

It gives us confidence to know that we've got a platform that can soak up and take all of that new traffic.

For Dunelm's platform team, this is just the start. The company is satisfied that its platform is faster, secure, and highly available, but Hayman believes that newer technologies, including Fastly's edge computing capabilities, will make the platform even faster in the years to come.