Senior Frontend Engineer - AI-Driven Design System

AI Startups UK; Greater London; Hybrid; GBP 100,000 - 140,000; Full time

Job summary

Synthesia, a world-leading AI video platform, seeks a Senior Software Engineer to own and evolve the design system foundation used across products.

You'll write high-quality React/TypeScript code, shape direction, and ensure AI-friendly components with accessibility and on-brand correctness for human and AI authors alike.

Collaborate with design, product and engineering to deliver a scalable, observable system, backed by Storybook and robust documentation.

Qualifications

• 5+ years as a software engineer, including senior-level, building frontend platforms with ownership of a design system or shared component library.
• Expert HTML, CSS and JavaScript/TypeScript with strong React experience.
• Strong command of component API design and developer experience for shared libraries.
• Experience or strong interest in making component libraries consumable by AI.
• Solid understanding of responsive design, cross-browser compatibility and web performance.

Responsibilities

• Build, scale and evolve the design system: components, tokens and docs.
• Extend the design system for AI-assisted development with Storybook as backbone.
• Design component APIs that resist misuse for both AI and human developers.
• Write high-quality frontend code (React/TypeScript) and ensure consistency across the org.
• Collaborate with design, product and engineering to ship production-ready components.
• Make components accessible by default, meeting WCAG 2.2 AA and keyboard/screen reader checks.
• Own the developer experience: docs, guidelines, versioning and migration paths.
• Implement theming, multi-brand theming and localization/RTL support.
• Shape technical direction and drive adoption across teams.

Skills

React

TypeScript

HTML

CSS

Design system

Storybook

Tools

Storybook

MCP

Job description

Synthesia, a world-leading AI video platform, seeks a Senior Software Engineer to own and evolve the design system foundation used across products.

You'll write high-quality React/TypeScript code, shape direction, and ensure AI-friendly components with accessibility and on-brand correctness for human and AI authors alike.

Collaborate with design, product and engineering to deliver a scalable, observable system, backed by Storybook and robust documentation.