Web Performance Engineering Lead

Salary: £53,000 - 93,000 per year

Requirements:

• Strong commercial front-end engineering experience with JavaScript, TypeScript, HTML, CSS, and modern frameworks
• Experience taking ownership of a high-traffic ecommerce website
• Deep understanding of Core Web Vitals and browser profiling tools such as Chrome DevTools, Lighthouse, and WebPageTest
• Practical experience with GA4, Google Tag Manager, consent management platforms, and the wider martech stack
• Magento or Adobe Commerce experience is a strong plus
• Ability to investigate issues independently, form hypotheses, and find answers without waiting for a perfect ticket
• Ability to explain complex website issues clearly to non-technical stakeholders
• A continuous improvement mindset, always looking for ways to make the website faster, simpler, and easier for customers

Responsibilities:

• Own front-end performance end to end across desktop and mobile
• Drive measurable improvements in Core Web Vitals, including LCP, INP, and CLS, on the journeys that matter most to revenue
• Analyse conversion data by device, browser, channel, and journey to identify friction that is costing sales
• Turn performance findings into a prioritised, commercially weighted roadmap
• Build and run experiments, including quick front-end variants, A/B tests, and feature-flagged releases
• Use experiment results to shape what we build next
• Protect tracking and measurement by working closely with Marketing and Data to catch discrepancies in GA4, GTM, and the data layer
• Review and control third-party scripts and marketing technology, challenging anything that slows the site down without enough value
• Use AI-assisted engineering tools to work faster
• Build monitoring that catches performance and tracking regressions before they become commercial problems

Technologies:

• AI
• CSS
• JavaScript
• Magento
• Marketing
• Mobile
• TypeScript
• Web

More:

We are Protein Works, a high-growth DTC nutrition brand with a clear mission to help people live healthier, happier lives through the power of nutrition. We are growing, investing, and hiring with purpose, offering the energy of a challenger and the foundations of a market leader. This is a hands-on engineering role at the point where Technology, ecommerce, and performance marketing meet, reporting directly into our Sales & Marketing Director and working closely with our Technology Director. We offer exclusive staff discounts, private healthcare, a birthday day off, a pension scheme, a unique bonus scheme, a cycle to work scheme, access to retail discounts, staff socials and events, a state-of-the-art PW Campus, WFH on Fridays, and refreshments on-site.

last updated 33 week of 2026