addmustard has an exciting opportunity for a UX & CRO Designer to join our digital marketing team in Brighton. Supported by our data insights team, the position will be design and UX led, and will also involve an equal element of UI expertise. You will be working alongside the performance and design team to input into our clients’ CRO strategies, plan and execute roadmaps and feedback performance to clients. You will play a key role in designing and executing important CRO tests across desktop, mobile and app, analysing the results alongside our data team and presenting important insight, analysis and recommendations to clients. Your aim will be to continuously improve our clients’ conversion KPIs, their customer experience and user journey by understanding trends and identifying UX opportunities, whilst considering the client’s strategy, products, market, customers and competitors.

You will be working with a team who are highly experienced in CRO & Analytics, who will expect to both mentor and collaborate with you, as well as providing training where needed. If you have a good knowledge of CRO, UX and UI, and are an enthusiastic, hardworking and confident communicator with 3-4 years’ design experience then this is the perfect role for you. Experience within a fast-paced commercial agency is also highly beneficial. If you have a portfolio of projects that include your approach to auditing and testing interfaces, web/mobile applications, we’d like to meet you.

You will be part of addmustard’s award-winning creative team in Brighton. You’ll be working with entrepreneurial businesses and high growth brands, so you will be challenged to develop your skills rapidly. This is a great opportunity to work within a multi-disciplinary team, where you’ll be participating in ground-breaking campaigns across all marketing channels. You will need to have the ability to work under pressure and to commit to delivering results on time.


Working closely with addmustard’s performance and design teams you will put together client CRO programmes involving the following:

  • Building CRO test hypotheses for multiple client websites.
  • CRO roadmaps, running A/B testing and MVT.
  • Identifying trends problem areas, and UX opportunities across our clients’ websites
  • Understanding our clients’ customers through user research, competitor and market analysis provided by both you and our data team.
  • Working to continuously improve brand and customer experience.
  • Creating or interpreting client briefs and going beyond the brief to communicate ideas and concepts to their full potential, with rationale to explain how and why.
  • Gathering and evaluating user requirements in collaboration with product managers and developers.
  • Presenting insightful analysis, concepts, and reporting to key stakeholders (often C-suite executives).
  • Taking CRO tests from briefing stage through to final prototype and build (front-end development knowledge is desirable but not essential).
  • Assisting with the preparation and communication of presentations and reports.

Desirable Skills and Experience

  • Proven experience in front-end development with a flair for user interface design
  • Ability to illustrate design ideas using storyboards, process flows and sitemaps
  • Ability to develop UI mock-ups and prototypes that clearly illustrate how sites look and function
  • Confident working in Sketch, Adobe CC and prototyping tools (Invision etc.)
  • Multivariate testing experience (A/B testing, MVT etc) and experience using testing tools such as VWO, Google Optimize or similar
  • Keen interest and knowledge of UX principles, and UI advancements
  • Experience using Google Analytics would be ideal but can be developed
  • Clear understanding and interest working and building basic HTML, CSS, JavaScript mark up
  • Excellent communication and interpersonal skills
  • Good organisational skills with the ability to prioritise, multi-task, work at pace and to tight deadlines.

addmustard benefits

  • Work with and be trained by industry experts at the forefront of digital marketing channels and platforms
  • Unlimited holiday!
  • Flexi time: flexible working hours and work from home opportunities
  • £500 personal training budget, allocated every 6 months
  • Pension scheme, gym membership and ride to work scheme
  • Be part of an amazing, sociable and supportive team with far too frequent nights out/socials/Friday pizza and beers and of course our annual Christmas party abroad!
  • Our senior management is open, honest and transparent. This means we regularly share financial, team, and client performance with the whole agency

How to apply

If we’ve piqued your interest, we’d love to hear from you. Send your CV and a covering letter to, explaining why you think you’d cut the mustard.

Please, no agencies. Thanks.

Key area: CRO, Data, UX, UI and Design
Contract: Full time