John Jost

Principal Frontend Engineer.

London-based frontend and UI specialist with over 20 years of experience delivering premium digital products. Focused on code quality, accessibility, performance, and consistency, with extensive knowledge of the GOV.UK Design System.

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Working at the intersection of UX, design and engineering, I specialise in Frontend Architecture and Design Systems for performance-critical applications, delivering scalable and inclusive experiences for high-traffic platforms. Operating both hands-on and at an architectural level, I lead teams that ship high-quality products for global audiences and clients.

Recent work

F1 Design System.

/Digitas UK

As a Principal UI Engineer for Formula 1, I led the development of their new Design System to support a globally scaled, high-traffic platform. Executed the full migration from a legacy platform to Next.js, providing continuity and practical architectural direction throughout the transformation. I was the primary technical authority for the frontend architecture, resolving ambiguity in design outputs, standardising UI behaviour, and improving performance, accessibility, and overall developer experience.

  • Design System
  • Figma + Supernova
  • Storybook + Chromatic
  • Style Dictionary
  • full-stack development
  • Next.js
  • Tailwind
  • a11y
See more projects →

Core focus areas

  • Design Systems & UI architecture.

    Architecture, scaling, best practices, governance and education (Atomic Design, Storybook, Design Tokens). Ensuring omni-channel consistency, reuse and cross-team alignment.

  • User interface engineering and UX collaboration.

    Implementing modular design patterns, interface composability, accessibility (a11y), web performance analysis and optimisation.

  • AI-assisted development with strict quality control.

    Leveraging tools like GitHub Copilot to improve velocity while enforcing high standards for accuracy, maintainability, and security. Defining guardrails and review practices to prevent low-quality or unverified AI-generated output.

  • Frontend tooling, frameworks and architecture.

    Server-side and client-side application design and development using React, Vue, (Next.js, Nuxt, Remix) and other frameworks, with emphasis on robust architecture, performance and long-term product support.

  • At-scale refactoring & legacy codebase transformation.

    Digital transformation, including migrating legacy technology stacks and improving system structure, reliability, and overall performance through large-scale refactoring.

  • Technical leadership & mentoring.

    Stakeholder management and communication. Leading teams to deliver high-quality solutions, fostering a culture of excellence and collaboration.

  • Engineering standards & code quality control.

    Establishing coding standards and best practices, reviews, static analysis, tooling.

  • Technical Project Management & delivery.

    Agile, Scrum, Kanban (Jira, Confluence), project planning, estimation, risk management.

  • Product development & delivery.

    Contributing to product direction through technical insight, rapid prototyping and close collaboration with design and business stakeholders.

  • Process definition & implementation.

    SDLC documentation, team onboarding, knowledge sharing, training and workshops.

Tools & technologies

AI-assisted development (AIAD)
Code analysis and refactoring with GitHub Copilot, Codeium, MCP UI, AI-assisted code review, refactoring, testing, debugging and documentation.
Modern / legacy frontend frameworks
React, Vue 2 + 3,TypeScript, vanilla JavaScript (ES6+)
Design systems, UI composability
Figma → Supernova → Storybook, component libraries
Full-stack, API design & server-side
Node.js, Express, Next.js, Nuxt, server actions, API routes, REST, tRPC, GraphQL
Headless CMS / e-commerce
Contentful, Sanity, Payload, Strapi, Shopify
Accessibility
WCAG 2.2, ARIA, a11y best practices
Platform
HTML5, Web APIs, DOM
CSS & styling
Design Tokens, CSS, SASS, LESS, Tailwind, responsive design, animation
Rendering patterns
CSR, SPA, SSR, SSG, ISR, PWA
State management
Redux Toolkit, Zustand, Context API, TanStack Query
Data layer
Prisma, Drizzle, PostgreSQL, MySQL, MongoDB
Realtime
WebSockets, Socket.IO
Authentication
OAuth2, JWT, Auth0, Clerk, Better Auth
Testing strategy
TDD, BDD, unit, integration and E2E testing, Jest, Vitest, Testing Library, Playwright, Cypress
Analytics & experimentation
Google Analytics, Google Tag Manager, A/B testing, personalisation