Senior Frontend Engineer (AI)

TL;DR

Senior Frontend Engineer (Astro/Sanity): Developing and scaling the marketing platform for a leading AI video platform with an accent on composability, content modeling, and SEO. Focus on building a robust section library, integrating AI-assisted development tools, and ensuring high performance across a global audience.

Location: Preference for London (in-office or remote). Also open to remote workers elsewhere in Europe (subject to compliance and right to work checks).

Company

Synthesia is the world’s leading AI video platform for business, used by over 90% of the Fortune 100.

What you will do

• Build and evolve the Astro component library and Sanity schemas for marketing pages.
• Design robust content models to ensure pages are correct by construction rather than by review.
• Implement Figma specs into production-ready, accessible, and responsive components.
• Extend the platform for AI-assisted development, enabling agents to generate on-brand sections.
• Own SEO integrity, including canonicals, sitemaps, structured data, and redirects.
• Maintain localization across nine locales and a translation pipeline for a global audience.

Requirements

• At least 5 years of software engineering experience, including 3 years at a senior level.
• Proven ownership of content models in Sanity, including proficiency with GROQ and Portable Text.
• Deep expertise in HTML, CSS, and TypeScript with a strong command of component API design.
• Ability to work end-to-end, owning SSR, serverless/edge runtimes, API routes, and SQL databases.
• Solid understanding of responsive design and WCAG 2.2 AA accessibility standards.
• Strong sense of craft and ability to balance design intent against engineering constraints.

Nice to have

• Experience with Astro, Cloudflare Workers, or AWS Lambda.
• Proficiency with Tailwind CSS v4 and token-based design systems.
• Interest in making component libraries and content models consumable by AI agents.
• Experience with large-scale SaaS marketing websites and high-traffic environments.
• Knowledge of analytics and server-side tagging implementation.

Culture & Benefits

• Work environment focused on building and high speed, avoiding excessive planning or politics.
• Culture that empowers the smartest and most unrelenting people to work without distractions.
• Clear work principles that guide decision-making and feedback.
• Full-time employment provided through OysterHR.

Hiring process

• 30-minute call with a Technical Recruiter.
• 45-minute call with the Head of Website regarding past projects.
• 75-minute practical collaborative exercise focusing on modeling and building a Figma spec.
• 60-minute call with leadership regarding collaboration, growth, and team fit.