Person holds a phone with FARFETCH app open

FARFETCH improves Core Web Vitals by 40%

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Founded in 2007 by José Neves for the love of fashion, and launched in 2008, FARFETCH began as an e-commerce marketplace for luxury boutiques around the world.

Today, FARFETCH is a platform with three business units: marketplaces, which include various channels and connect customers in over 190 countries to 1,400 of the world’s best brands, boutiques, and department stores; the platform solutions business unit, which offers end-to-end commerce solutions to accelerate growth and innovation for luxury brands and retailers; and the NGG brand platform layer, which includes brand design, production, and development.

Improving reliability and decreasing load times

When Google introduced Core Web Vitals (CWV) in early 2020, the user experience metrics became a guiding light for the FARFETCH engineering team. CWV provides a comprehensive, easy-to-understand set of metrics that can be tied directly to the customer experience. Improving CWV means that a site loads faster and is easier to interact with. One of the most important CWVs for FARFETCH is Largest Contentful Paint (LCP), the amount of time it takes to show the user the largest content on the site, and Time to Interactive (TTI), the amount of time it takes for a site to be fully interactive for the user. 

“Core Web Vitals give us the perception of what the user experience on our sites is. It has a direct impact on our ability to generate revenue for the business. Fast loading times that enable customers to quickly interact with items is instrumental to enhancing the online purchase experience,” says Marcus Freire, principal software engineer at FARFETCH. 

In early 2021, CWV presented a lot of challenges. Bots were plaguing operations for the FARFETCH marketplace, and a tangled web of third-party microservices made it difficult to pinpoint the root cause of the problem. The FARFETCH engineering team was pressured to fix multiple issues. “We knew we had to introduce changes that would go deep into tackling some root causes,” says Manuel Garcia, distinguished engineer at FARFETCH.

Drilling down on root causes

To cut through the complicated architecture of third-party services, FARFETCH defined the most important metrics within New Relic and used those metrics to conduct A/B tests to identify opportunities for performance improvement. 

New Relic application performance monitoring (APM) allows FARFETCH engineering teams to be proactive instead of reactive. When a bug emerges, New Relic provides visibility into all parts of the system—including third parties. Deployment markers and change tracking immediately reveal the cause of an issue and allow FARFETCH to see the result of a specific deployment. Engineering teams can then run A/B testing and gain immediate feedback on how these tests impact user experience. It also means that FARFETCH can prioritize opportunities in terms of ease of deployment and potential outcomes. New Relic dashboards provide instant visibility into the impact of a certain change action. This information—easy to acquire and to understand—gives the engineering team a valuable resource when communicating with other areas of the business, like sales and marketing.

New company culture spotlights performance

With enhanced visibility, FARFETCH has achieved a significant milestone by directly correlating engineering improvements with tangible business outcomes. 

“We have developed a business calculator that enables any stakeholder to project the potential revenue generated by a specific change. For instance, if we enhance the LCP metric on a particular page by half a second, we can estimate the corresponding increase in business revenue resulting from that change. By connecting time and money through our monitoring and tracking tools, we have provided a comprehensive understanding of the impact of these improvements. This alignment of metrics ultimately enhances the likelihood of customers making a purchase,” says Manuel.

FARFETCH achieved remarkable improvements in technical performance, with an almost 10% enhancement in TTI, a 40% improvement in LCP, and a substantial reduction in response times on the API ranking service, from nine seconds to one. Acknowledging the influence of various third-party services on performance, FARFETCH utilized benchmarks to assess the impact of adding or removing specific microservices. These metrics also enabled FARFETCH to place performance within a broader industry context. "When we compare our results with our competitors in the same business area, it’s clear we had very impressive results," Marcus says.

The increased visibility provided by New Relic sparked a significant cultural shift for FARFETCH. The entire organization recognized the value of technical performance in its marketplace. Emerging from the Core Web Vitals crisis, the engineering team can now effectively showcase the significance of improvements with data.  "I have seen the company place a greater emphasis on performance. Marketing sees how important it is. Our stakeholders recognize its significance. It was a challenging period, but we are very excited with what we achieved," Manuel says.

40%

improvement in Largest Contentful Paint

10%

reduction in Time to Interactive

8

second reduction in rank API response time