OverviewJob Description

Shape the design system behind a unicorn AI- SaaS platform, scaling globally at speed.

Why This Role?

Stax

is partnering with a

unicorn AI- SaaS scale-up

that’s transforming how organisations use AI. Now they’re building a

London engineering hub . Join as a UK

founding engineer -

hybrid working, high impact, and the chance to shape a

category-defining platform

from day one.

The OpportunityThis is a systems-level role at the intersection of design and engineering.

You’ll be at the heart of a platform that’s changing how organisations use AI for customer support and product operations.

In just four years, the team has:

Pushed browser limits

with D3-powered visualisations and real-time dashboards

Open-sourced client-side analytics

on DuckDB, bringing OLAP to the edge

Built AI- UIs

that feel fast, intelligent, and fun

Scaled a themeable design system

adopted across multiple products and platforms

Introduced micro-frontends

that power independent, high-velocity teams—and let customers embed their own modules directly in the product

Delivered deeply configurable UIs

where layouts, components, and visualisations can be reshaped end-to-end via declarative config

Your role: define the system that makes every pixel seamless, scalable, and lightning-fast.

What You’ll Do

Evolve the design system: tokens, theming, accessibility, visual

Build React + Web Component libraries for core + embedded apps

Advance tooling: Storybook, Chromatic, Figma plugins

Set standards and governance across design + engineering

Deliver performant layouts and visualisations at scale

Mentor peers on accessibility and performance-first development

Tech Ecosystem You’ll ShapeDesign Tokens · Figma API · Storybook · React · Web Components · TypeScript · Tailwind CSS · Vite · NextJS · Jest · Cypress · Playwright

What You Bring

8+ years in large-scale web apps, 2+ in design-system architecture

Strong perspective on tokens, theming, multi-brand support

Mastery of React + TypeScript, with library publishing experience

Accessibility leadership (WCAG, ARIA, keyboard nav, contrast)

Fluency in CSS methodologies and testing frameworks

Excellent communication skills to align design, product, and engineering

Bonus points

for OSS contributions, Figma plugins, or micro-frontend orchestration

Culture and Impact

Speed with craftsmanship : fast feedback, continuous delivery, peer reviews

Performance-first mindset : Core Web Vitals as product metrics

Inclusive and global : teams across the US, Europe, and India

Autonomy with accountability : design, guide, measure, iterate

London hub : hybrid model, build the team and culture from the ground up

Why join?Your design system will power products used by some of the world’s most ambitious teams. Join at a moment of hyper-growth and play a defining role in one of the most exciting SaaS platforms in the world.

Stax welcomes applications from all backgrounds. Our client unfortunately can''t offer visa sponsorship.

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