Get AI‑powered advice on this job and more exclusive features.

First of all—Who are we and why do we exist?

addmustard is an award‑winning brand, marketing, and technology agency for entrepreneurs.

We combine the strategic and creative firepower of an advertising agency with the precision and incision of a digital marketing agency, supported by a global network of specialists.

A team of 35 brilliant marketing, data, brand, and tech experts – a core team based in Brighton and Soho – creates value for our clients’ businesses and brands.

About the role

This role exists solely to generate sustainable, meaningful improvements that build value in our clients’ brands. You’ll bring together the science of user psychology and the art of digital experience, constantly challenging assumptions and testing the unexpected to deliver real impact.

What will you be responsible for?

You’ll deliver top quartile conversion rates for all of our clients, ensuring optimum ROI from their brand, marketing and technology investments. You will analyse conversion‑rate factors, benchmark against competitors, design effective solutions in collaboration with our Performance, Creative, Brand, and Technology teams, and blend qualitative and quantitative data to create a unique, high‑performance brand and user experience.

Day‑to‑day responsibilities

• Lead the research and execution of CRO roadmaps across a diverse portfolio of entrepreneurial businesses.
• Build and implement test hypotheses using tools like VWO, A/B Tasty or Mida.
• Analyse user behaviour via GA4, Hotjar, Clarity, SessionCam or equivalent and translate insights into prioritised test plans.
• Identify UX barriers and improvement opportunities across key customer journeys, suggesting actionable development changes where needed.
• Plan and lead quantitative and qualitative research, including user journey audits, customer surveys and user testing.
• Translate research into wireframes, storyboards, user flows or annotated mock‑ups using Figma, InVision and Adobe XD.
• Work collaboratively with performance and creative teams to ensure optimisation insights feed into broader campaign strategy.
• Lead client workshops and present CRO insight and strategy clearly to C‑suite stakeholders.
• Maintain and iterate reporting dashboards, clearly communicating performance uplift, confidence intervals and business impact.
• Stay informed about UX best practices, psychological principles of persuasion, and the latest CRO testing tools.
• Use development skills (HTML/CSS/JS) to implement changes to web pages, testing and tracking systems as part of the CRO process.

Experience and skills required

• Hands‑on experience designing and running A/B and multivariate tests with major testing platforms.
• Deep understanding of user‑centred design principles, conversion theory and behavioural analytics.
• Strong grasp of tools like GA4, VWO, Looker Studio, Hotjar, Clarity and Tag Manager.
• Ability to build test ideas from research, prioritise them using frameworks like ICE, PXL and present a clear rationale for each decision.
• Exceptional communication and storytelling skills – both written and verbal – to present technical insights in an accessible and actionable way.
• Experience using visualisation tools to present insight in an accessible, strategic format.
• A highly collaborative mindset with the confidence to challenge assumptions and champion evidence.
• Experience using version control tools like Git to manage and track development efforts.
• Familiarity with agile methodologies or sprint‑based delivery processes.
• Knowledge of customer journey mapping and service design principles.
• Experience supporting new business efforts, bringing expertise in conversion and technical optimisation to new pitches or proposals.
• Familiarity with advanced web frameworks like React, Vue.js or Angular to optimise front‑end performance and interactivity.
• Technical SEO experience, including page speed optimisation, lazy loading and image compression to improve load times and website performance.

What does it mean for you?

We pride ourselves on being bold, energetic, precise and irreverent. Equally, we are open, honest, innovative and hard‑working in everything we do for our entrepreneurial clients, our team and our network. You’ll be surrounded by a flat and integrated organisational structure that values good ideas and celebrates real‑world impact.

Benefits

• Work across diverse audiences, markets, sectors and projects, each with unique challenges.
• Learn from industry experts at the forefront of brand, marketing and technology.
• Access to senior management who are open, honest and transparent and who share company performance openly.
• Flexible hours and a hybrid working structure across home, Soho and Brighton.
• Be part of a supportive and sociable team.
• Active social life: regular lunches, dinners, team events and holidays.
• 10% annual bonus scheme (after first year).
• £1,000 personal training budget per year.

How to apply

If you’re interested, send your CV and cover letter to talent@addmustard.com explaining why you’d cut the mustard. Please, no agencies. Thanks.

Seniority level

Mid‑Senior level

Employment type

Full‑time

Job function

Business Development and Sales

Industry

Advertising Services