Product Designer (UX/UI)

About HASH

HASH's open-source platform helps firms integrate both structured and unstructured information into knowledge graphs that support simulating, optimizing and automating processes. Our mission is to solve information failure, and help everybody make the right decisions. To that end, we're unapologetically excited. Actions speak louder than words, and we measure performance by output. We prioritize speed, and measure product delivery timelines in hours and days, not months and years. We value high-energy, high-expectations people who do what they say and say what they mean. We're committed to building a high-commitment, high-trust environment, and believe that the best teams are most productive together, in-person. This opening is for a position in London (United Kingdom), however we also have an in-office opening for the same position in Berlin (Germany).

About the role

As a senior Product Designer working on Novel AI & World Modeling Interfaces you’ll be the steward of our end-to-end product experience: establishing a robust Figma design system, crafting high-fidelity prototypes and production-ready designs, and partnering with engineers to ship pixel-perfect features. You’ll join a cross-functional squad of UX researchers, UI designers, AI scientists, frontend developers, and product managers pushing the limits of what’s possible in the browser, building systems to deliver “Safeguarded AI”.

What you'll work on

• Own our Figma design system: produce scalable components, typographic styles, tokens, and documentation for use across multiple high-calibre internal and external teams
• Translate user storiesinto journey maps, wireframes, and polished UI ready for user testing cycles, and later production
• Develop intuitive, informative interfaceswhich enable non-technical users to create models of real world processes, providing abstractions and assistance on top of the complexity of the underlying theory
• Build interactive prototypes (Figma/Web)to validate flows and micro-interactions with test users
• Facilitate design critiquesand collaborate closely with engineering to ensure design intent is faithfully realized
• Champion accessibility and inclusive designacross typography, color, motion, and copy

Must have

• Demonstrable experience designing complex web apps with a modern design-system mindset
• Advanced mastery of Figma: beyond ordinary component libraries, variants, tokens, shared styles, and auto-layout
• Strong visual craft (typography, colour, grid) paired with systematic thinking
• Comfort prototyping at multiple fidelities and presenting rationale to technical and non-technical stakeholders
• Solid understanding of WCAG 2.2 and pragmatic accessibility techniques
• Excellent written & verbal English; thrive in async, documentation-heavy culture

Nice to have

• Experience designing data-dense products (simulations, modeling, analytics), AI-user interactions, or user-built views and models (e.g. process flows, dashboards).
• Hands-on UX research: facilitating questionnaires/workshops, planning studies, analysing insights, turning findings into action
• Interest in real-time collaboration (i.e. multiplayer editing) and how it shapes UX patterns

Benefits

We offer leading equity-weighted total compensation, including competitive salaries and tax-advantaged options. We also offer:

• Employer pension contributions
• 30 days paid flexible leave
• Twice-yearly in-person team retreats around the world

HASH's founders have previously sold companies for hundreds of millions (and billions) of dollars.

In London, this role will be paid a £70,000-110,000 base + meaningful equity.