Senior Frontend Engineer, Marketing Website

About the role

You will be a co-owner of the platform behind synthesia.io, which serves as the component library, content model, and rendering stack for every page on the Synthesia marketing site. You will shape technical direction and make key decisions with the team, likely focusing on one area while maintaining context across the entire system. This is a hands-on engineering role where your primary output is high-quality component and schema code, along with the tooling that enables others to build with it. You will ensure that millions of monthly visitors experience a fast, reliable, and trustworthy interface that supports business growth and conversion. The role directly influences how effectively marketers and AI agents can build pages without breaking design, performance, or SEO. You will be accountable for the end-to-end quality of the customer-facing surface, balancing creative design intent with robust engineering practices.

Key facts

What you'll do

• Build, scale and evolve our section library: the Astro components, Sanity schemas and design tokens that let us compose marketing pages consistently and accessibly.
• Own the content model. Design schemas that resist misuse, so an editor, or an agent, can build a page that is correct by construction rather than correct by review.
• Translate Figma component specifications into production-ready code that is responsive across mobile, tablet and desktop, accessible by default, and pixel-perfect with respect to the design intent.
• Extend the platform for AI-assisted development, enabling coding agents to generate on-brand, on-spec sections from a design spec as reliably as a human developer.
• Take ownership of SEO integrity as a first-class engineering concern, including canonicals, sitemaps, structured data, redirects, and prevention of traffic cliffs on launch.
• Raise the bar on engineering standards across the website surface through thorough code review, reusable patterns, and targeted tests around the parts of the system that actually break.
• Maintain and extend localisation across nine locales and the translation pipeline, ensuring the system works seamlessly for a global audience.
• Shape the technical direction of the website platform over the next 6 to 12 months and champion its adoption with the people who publish content on the site.
• Collaborate closely with designers, product managers, and cross-functional partners to turn ambiguous requirements into well-defined, technically sound solutions.
• Contribute to architectural decisions that affect performance, scalability, and maintainability of the marketing site at global traffic levels.
• Implement robust data-fetching strategies that balance freshness, resilience, and speed while working with CMS sources and edge delivery networks.
• Mentor junior engineers and pair with them on complex front-end challenges to improve overall team capability and consistency.
• Define and enforce accessibility standards, integrating WCAG 2.2 AA considerations into the definition of done for every feature.
• Instrument and monitor user interactions, conversion events, and performance metrics to inform iterative improvements on the marketing site.

Requirements

• At least five (5) years as a software engineer, including three (3) at senior level, building front end for content-driven or marketing platforms.
• Real ownership of a content model in Sanity. You have designed schemas other people had to live with, and you have opinions about references versus embedded objects, when a variant belongs in the schema versus at runtime, and how to stop a section library from sprawling. GROQ and Portable Text are familiar territory.
• Deep front-end expertise: expert HTML, CSS and TypeScript, with a strong command of component API design and the developer experience of a shared library.
• You can work end to end. Comfortable owning the server side as well as the front end: SSR, serverless and edge runtimes, API routes, a SQL database, secrets, and CI. You should be able to take a feature from schema to component to the route that serves it without handing off, and be comfortable debugging something that only reproduces in production.
• Solid understanding of responsive design, cross-browser compatibility, and web performance, and comfort building to WCAG 2.2 AA. Accessibility is part of your definition of done, not a separate pass.
• You care that marketing sites are measured on performance, SEO, analytics events, and conversion, and you are happy being accountable to those numbers.
• A strong sense of craft and attention to detail, and the judgment to balance design intent against engineering constraints.
• Strong communication and collaboration skills. You explain your reasoning, review generously, and treat levelling up the people around you as part of the job.

Nice to have

• Prior experience working on a large SaaS marketing website, at real traffic and with real stakes attached.
• Astro, or another islands or static-site framework.
• Cloudflare Workers, or another edge or serverless platform.
• Experience with AWS Lambda.
• Tailwind CSS v4, and experience working from Figma tokens at scale.

Practical notes

This role is full-time based in London. Relocation support may be available for candidates who require it. The position does not require travel. Candidates must be eligible to work in the United Kingdom without sponsorship. Applications will be reviewed on a rolling basis until the role is filled.