Lead Front End Engineer (City of London)

Company Description

Every company in the world needs to understand who they are doing business with. We are re-imagining how humans find, read and distil knowledge from the internet – at unprecedented scale and accuracy, to answer critical questions about suppliers, donors, investors and third parties. We are addressing a sector-independent problem for a global market. We are pioneers, working at the forefront of AI and applied research, to build a fully distributed, heterogeneous and scalable system, using the latest technologies. We help the world ‘do better business, faster’. Our clients include the world’s leading charities, universities, law firms and financial institutions. Using Xapien, in minutes, they can do work that previously took hours and days. We have over 100 customers, in 3 continents, last year we doubled in size and this year we plan to triple. Our investors include tech founders, professional investors and recognised institutions, including Sequoia Capital.

The challenge

We’re about to rewrite our entire front-end application—from scratch. This includes introducing a completely new design system and upgrading our front-end architecture. It’s a major technical undertaking that needs leadership, clarity of vision, and technical excellence. We’re looking for someone to lead the charge: a senior front-end engineer who can architect a modern, scalable, and maintainable codebase, mentor others, and collaborate cross-functionally to deliver a best-in-class product experience.

The role

As Lead Front End Engineer, you’ll be responsible for designing and executing the complete rebuild of our front-end application. You’ll work closely with product, design, and back-end engineering teams to deliver a seamless, performant, and scalable user experience. You’ll also play a critical role in shaping our design system, driving front-end best practices, and mentoring the wider engineering team. This is a hands-on leadership role—one where you’ll write code, make architectural decisions, and guide the front-end direction of the company.

Here’s what you will be responsible for:

• Owning the architecture and implementation of the new front-end application.
• Building a high-performance, scalable, and maintainable React + Redux application.
• Designing and documenting a reusable, accessible, and elegant design system in collaboration with the design team.
• Leading front-end technical decision making, establishing best practices and tooling.
• Improving developer experience and tooling across the front-end codebase.
• Collaborating with product managers, back-end engineers, and designers to ensure smooth and scalable delivery of new features.
• Driving performance improvements and usability enhancements across the UI.
• Supporting internal stakeholders (e.g. marketing, customer success) with front-end requirements like analytics, tracking, and landing pages.

Qualifications

Must-haves to be successful in this role:

• Deep knowledge of JavaScript, HTML/CSS, and TypeScript.
• Extensive experience with React.js and state management using Redux (or similar).
• Demonstrated experience applying mobile-first design principles to create responsive and accessible UIs.
• Proven track record in leading the architecture of modern front-end applications.
• Strong understanding of front-end performance and optimisation techniques.
• Experience building and maintaining a reusable component library or design system.
• Proven technical or team leadership experience and a passion for mentoring and coaching.
• Comfortable working in Agile teams, conducting code reviews, and participating in pair programming.
• Strong communication skills—capable of articulating technical decisions clearly and collaborating across functions.
• A desire to lead, mentor, and help others grow.

Nobody can do everything but here’s a few related things we’re interested in:

• Familiarity with tools such as Storybook, Figma, CI/CD pipelines, and GitHub workflows.
• Solid awareness of back-end integration (experience with Go is a plus).
• Experience scaling front-end applications in a growing SaaS environment.
• Familiarity with AWS tooling relevant to front-end infrastructure.
• Exposure to accessibility standards and inclusive design practices.
• Enthusiasm for clean, well-documented, and testable code.
• A thoughtful approach to refactoring legacy systems.

Additional Information

• Equity in the business in the form of shares – You will own a meaningful part of the business through our employee shares & equity programme.
• Unlimited Paid Time Off for you to take time to recharge.
• A wellness & professional development fund of £1,000 per year – including access to Wellhub - formerly Gympass.
• Private health and Life insurance.
• High-spec MacBook + £200 for equipment setup.
• Regular team lunches and social events, from go-karting to mini golf to karaoke to rounders in the park.
• X day – one whole company day off every year so we can all switch off Slack and reset.
• Flexible working + flexible hours (2 days per week in our WeWork in Moorgate).

Please note, we cannot offer sponsorship to applicants (or transfer existing visas) at present.

Salary: up to £110,000 + bonus + equity (dependent on experience)

Our Values

• Take ownership – We keep our organisation simple, valuing people over policies. We encourage ownership and decision-making.
• Better together – We care about each other and go out of our way to help colleagues succeed. We value relationships and take a genuine interest.
• Transparent – Our business is creating transparency in business relationships; so internally we are ‘default share’, even when it feels uncomfortable.
• Glass-half-full – This is about being real but still choosing to be optimistic. We celebrate wins and encourage each other to build forward.
• Be pioneers – We are leaders not followers – bold, ambitious and can-do.
• Move fast – This is our moment to make our mark on the world. So we work to ambitious deadlines, launch fast and iterate, always streamline, and remain decisive amid huge uncertainty.
• Value learning – We are all learning, always. We take time to explain, even if it’s quicker to do it ourselves.
• Always decent – We are polite, thankful and straightforward. Everyone is down-to-earth, informal and approachable.
• A players – Working here should be stretching and exhilarating. We only hire, and keep, the best, enquiring people that will keep us on our toes.