Senior Product Designer (AI Design Agency)

Mustard Navy is an award-winning product design agency dedicated exclusively to AI products. We help category-defining founders, scale-ups, and private-equity-backed innovators transform raw, emerging machine learning technology into impactful, human-centric user experiences. From rapid vision prototyping to zero-to-MVP builds in deep tech, health tech, and beyond, we build "Design Intelligence" that scales.

As code gets cheaper, well-crafted interfaces matter more. Graft and craft are what set our work apart, and we want to raise the bar further.
We're looking for a Senior Product Designer who can own projects and deliver across the board, with a real spike in visual design. You'll be fluent in AI-driven ways of working, and you'll have the experience and taste to craft great interfaces without a prompt box. You'll set the standard for how our work looks and how we critique it, and make everyone around you better. You'll also help shape who we are, defining our culture and growing the agency with us.

About you

You're likely a great fit if you:
Have a portfolio of shipped digital products that goes beyond standard UI patterns, with visual craft you can talk about in detail: typography, layout, hierarchy, colour and motion.
Can take a project from brief to polished prototype, framing the problem, testing concepts through wireframes, and refining the final interface.
Understand how designs get built, and have experience with design systems, frontend frameworks or animation.
Think critically and zoom in and out of problems with ease.
Are passionate about non-standard interfaces, such as conversational or generative UI, interactive data visualisation, mixed media, and others.
Understand foundational design principles for AI and data-rich products.
Are comfortable working with AI throughout your process, and have the taste and judgement to know when its output is good enough, and when it isn't.
Explain design decisions confidently, and give and receive critique well.
Thrive in ambiguity and find paths forward independently.
Gravitate towards impact-driven outcomes.
Learn through hands-on experimentation, and enjoy sharing what you find.
Your background might combine startups, agencies, consultancies or product teams, totalling around 5+ years. However, mindset and skills matter more than rigid criteria. You must be legally allowed to live and work in the UK.
What you'll do
This is a dynamic, hands-on role typical of a fast-growing startup agency. Most days, you'll:
Hold day-to-day responsibility of product design projects.
Understand client context and requirements, assisting in research if required.
Develop wireframes to test a broad variety of concepts.
Craft creative, visually stunning interfaces and interactive prototypes.
Build and evolve design systems that help our clients to scale their products.
Drive innovation while balancing client constraints.
Contribute broadly to agency growth and internal initiatives.
Critically, you'll:
Work closel