Web Performance Engineering Lead - Protein Works

Job Advert

We’re looking for a Web Performance Engineering Lead to take ownership of the technical performance of the Protein Works website.

This is a hands-on engineering role sitting at the point where Technology, ecommerce and performance marketing meet.

You’ll be responsible for making our website faster, more stable and easier to buy from, identifying the technical issues and opportunities that have the biggest impact on customer experience and commercial performance.

We’re looking for someone who thinks beyond whether a website simply “works”. You’ll care about every millisecond of load time, every unnecessary script, every broken tracking event and every point of friction standing between a customer landing on our website and completing their order.

You’ll report directly into the Sales & Marketing Director, giving you close access to our commercial priorities, performance data and experimentation roadmap. You’ll also work closely with our Technology Director, ensuring everything we build meets the technical standards required of a high-growth ecommerce business.

This role comes with genuine ownership. You’ll be expected to spot opportunities, investigate problems, build solutions and measure whether they made a difference.

What You'll Do

• Own front-end performance end to end across desktop and mobile, driving measurable improvements in Core Web Vitals (LCP, INP and CLS) on the journeys that matter most to revenue.
• Dig into conversion data by device, browser, channel and journey to find where friction is costing us sales, then turn those findings into a prioritised, commercially weighted performance roadmap.
• Build and run experiments, from quick front-end variants to full A/B tests and feature-flagged releases, and use the results to shape what we build next.
• Protect our tracking and measurement, working closely with Marketing and Data to catch discrepancies in GA4, GTM and the data layer before they cost the business insight.
• Review and control third-party scripts and marketing technology, challenging anything that slows the site down without earning its place.
• Use AI-assisted engineering tools to work faster, and build the monitoring that catches performance and tracking regressions before they become commercial problems.

Ideal Candidate

• Strong commercial front-end engineering experience (JavaScript/TypeScript, HTML, CSS, modern frameworks) and comfortable taking ownership of a high-traffic ecommerce website.
• You genuinely know your way around Core Web Vitals and browser profiling tools such as Chrome DevTools, Lighthouse and WebPageTest, and can turn “why is this slow” into a shipped fix.
• Practical experience with GA4, Google Tag Manager, consent management platforms and the wider martech stack; Magento or Adobe Commerce experience is a strong plus.