Dixons Carphone
- Title: Developer
- Website: https://www.currys.co.uk/
Company
Dixons Carphone was the previous name of Currys plc. Currys plc is a leading omnichannel retailer of technology products and services, operating online and through 719 stores across six countries.
Team
The Searchlabs team consisted of three additional senior developers, one QA, one product owner/scrum master, and one part-time team lead. The team operated as a true Scrum team, empowered to take full ownership of the search API. In my role as a senior developer (contractor), I utilized my expertise to suggest and implement improvements to the search API.
Challenge
Beyond BAU development, I focused on improving the resilience, performance, and search-result quality of the Currys search API, which underpins product discovery across the ecommerce platform. The search API supported high request volumes and was a core driver of online sales, making stability and performance essential.
Working as part of a senior engineering team, I led initiatives to introduce automated performance validation, improve observability, and ensure search-relevancy changes could be measured reliably before release.
API Performance & Load Testing: I automated load testing and encapsulated it in a Docker container, then established baseline performance metrics. Performance testing was added to the CI pipeline so that performance degradation would fail the build. I also added tooling to run controlled load tests against deployed environments to verify that auto-scaling behaved as expected under peak load.
Search Relevancy: I built a framework to objectively measure search-quality changes using the Wilcoxon signed-rank test to compare product ranking positions across the top 1,000 user searches. The tool highlighted statistically significant ranking changes and allowed the team to drill down into individual queries to understand the real-world impact of algorithm updates.
Other contributions included migrating services to Docker Compose, enhancements to the search results and back office tooling, and configuration of OpenDistro Elasticsearch monitors.
Results
The introduction of automated performance testing meant that degradation could be detected before release, allowing issues to be corrected before impacting the production site or customer experience.
The search-relevancy testing framework gave the team objective metrics to assess ranking changes, significantly reducing the risk that algorithm updates would negatively affect key product journeys.
Together, these improvements strengthened the reliability of a core revenue-generating system and provided the team with practical tools to make iterative improvements with confidence.