Lead CRO Developer

Hackajob Ltd; Holbeck; Hybrid; GBP 61,000 - 94,000; Full time

Benefits offered by this job

Hybrid working

Profit share

Jet2 discounts

Job summary

Hackajob Ltd in the United Kingdom is seeking a Lead CRO Developer to own A/B and multivariate testing across digital platforms. You will code in JavaScript, HTML and CSS to build experiments and personalisation campaigns that boost conversion and engagement, collaborating with UX, Analytics and Marketing to translate ideas into measurable tests.

You will mentor engineers, review code, drive technical governance, and ensure tests are performant with respect for Core Web Vitals.

Qualifications

• Extensive experience developing A/B tests, personalisation campaigns or optimisation solutions.
• Expert knowledge of JavaScript, HTML and CSS with modern web development principles.
• Experience with experimentation platforms such as Optimizely, Adobe Target, VWO, AB Tasty or similar.
• Proven leadership experience, mentoring developers and promoting engineering best practice.
• Strong understanding of website performance, accessibility, cross-browser compatibility and responsive design.
• Experience working with UX, Product and Analytics teams through the experimentation lifecycle.
• Excellent problem-solving skills with a focus on measurable improvements to customer experience and commercial performance.
• Strong communication and stakeholder management, able to explain technical concepts clearly.

Responsibilities

• Lead the technical delivery of A/B and multivariate tests across digital platforms.
• Develop customer experiences using JavaScript, HTML and CSS to create experiments and personalisation campaigns.
• Collaborate with UX, Analytics and Marketing to translate ideas into measurable experiments.
• Champion experimentation methodologies, coding standards and technical governance.
• Minimise impact on page performance, accessibility and Core Web Vitals while maintaining experience.
• Mentor developers, conduct code reviews and evolve development standards.
• Configure and develop within platforms like Optimizely or Adobe Target for client-side and server-side experiments.
• Stay up to date with CRO techniques, browser capabilities and front-end technologies.

Skills

A/B testing

Personalisation

Optimization

Tools

JavaScript

HTML

CSS

Optimizely

Adobe Target

VWO

AB Tasty

Job description

Salary: £61,000 - 101,000 per year

Requirements:

• Extensive experience developing A/B tests, personalisation campaigns or optimisation solutions within a commercial environment.
• Expert knowledge of JavaScript, HTML and CSS, with a strong understanding of modern web development principles.
• Experience working with experimentation platforms such as Optimizely, Adobe Target, VWO, AB Tasty or similar.
• Proven leadership experience, including mentoring developers, leading technical discussions and promoting engineering best practice.
• Strong understanding of website performance, accessibility, cross-browser compatibility and responsive design.
• Experience working alongside UX, Product and Analytics teams throughout the experimentation lifecycle.
• Excellent problem-solving skills with a passion for delivering measurable improvements to customer experience and commercial performance.
• Strong communication and stakeholder management skills, with the ability to explain technical concepts to both technical and non-technical audiences.

Responsibilities:

• Lead the technical delivery of A/B and multivariate tests, ensuring high-quality, performant and scalable implementations across our digital platforms.
• Develop customer experiences using JavaScript, HTML and CSS, creating experiments and personalisation campaigns that improve conversion and user engagement.
• Work closely with UX, Analytics and Marketing teams to translate ideas into measurable experiments and optimisation opportunities.
• Champion experimentation methodologies, coding standards and technical governance, ensuring reliable and statistically sound test implementations.
• Ensure experiments have minimal impact on page performance, accessibility and Core Web Vitals while maintaining an excellent customer experience.
• Mentor developers, conduct code reviews, support technical decision making and help evolve the teams development standards and ways of working.
• Configure and develop within experimentation platforms such as Optimizely, Adobe Target or similar technologies, supporting both client-side and server-side experimentation where appropriate.
• Stay up to date with emerging CRO techniques, browser capabilities and front-end technologies, identifying opportunities to improve our experimentation capability.

Technologies:

• CSS
• Support
• JavaScript
• Marketing
• Web
• UX UI Design

More:

hackajob is partnering directly with Jet2.com and Jet2holidays to hire for this role. We are looking for an experienced Lead CRO Developer to join our Digital Experience team and help shape the future of experimentation and optimisation across our websites. We offer hybrid working, with time in the office approximately 2 days per month, a generous discretionary profit share scheme, and colleague discounts on Jet2.com flights and Jet2holidays packages. At Jet2.com and Jet2holidays, we work together to deliver an amazing journey, literally, driven by a Customer First ethos and a commitment to creating unforgettable package holidays and flights. We value our people and are redefining travel experiences for millions of passengers.

last updated 38 week of 2026