Problem
A global fashion brand's eCommerce site had degraded performance over time. Lighthouse scores on mobile were below target. The site had accumulated third-party scripts based on client requirements, unoptimised asset delivery, and rendering bottlenecks that had gone unaddressed.
Role
Brought in as Lead Performance Engineer for a focused engagement. I ran the full performance audit, defined the remediation roadmap, implemented high-impact fixes hands-on, and worked with the existing team to deliver the remaining improvements. Also established a performance budget process to prevent regression after the engagement.
Stack
- Audit tooling: Lighthouse, WebPageTest, Chrome DevTools
- Build analysis: Webpack bundle analysis — identified dead weight in script payload
- Third-party audit: Reviewed scripts loaded per page against actual requirement; flagged unnecessary load
- CI: Lighthouse CI integrated into pipeline as part of budget enforcement
Outcome
- Lighthouse scores improved ~20% from a 60+ baseline on mobile
- Rendering bottlenecks and asset delivery issues resolved — reduced layout shift and render-blocking load
- Performance budget process established — prevents score regression as site evolves
- Engagement delivered as a standalone dedicated sprint with hands-on implementation