The Sr. Software Engineer (FE) will lead the development of scalable frontend applications using React. Responsibilities include systems design, testing strategy, performance optimization, AI integration, and mentoring.
Who We Are
At Firstup, our mission is to improve the employee experience at every moment that matters, large and small. As the communication pipeline for the world's workforce, we now serve 40 of the Fortune 100 companies, reaching and connecting more than 17 million employees daily.
Our employees are experts in the employee experience, workforce communications and technology.
Joining Firstup means joining a movement to make work better for every worker. As the world’s first intelligent communication platform, Firstup meaningfully engages employees at every moment from hire to retire, and delivers engagement insights to help companies support, promote and retain their talent. Our movement has taken root and is evident in our world-class customer base. Now we need your help. Ready to make a difference in the world?
Job Summary
The Sr. Software Engineer (FE) will lead the development of scalable, high-performance frontend architectures. You will drive engineering excellence through modern React patterns, robust testing strategies, and the strategic use of AI-assisted development tools to accelerate delivery without compromising quality.
Responsibilities
- Core Engineering: Build scalable frontend applications using modern React patterns and a component-driven architecture.
- Systems Design: Own the design and implementation of a reusable, accessible component library and documentation.
- Testing & Quality: Define the frontend testing strategy (Unit, Integration, E2E) including visual regression and user interaction coverage.
- Performance & Reliability: Optimize client-side performance and ensure production readiness through observability, error monitoring, and rapid incident resolution.
- AI Integration: Leverage and advocate for AI-assisted tools (e.g., GitHub Copilot, Claude) to accelerate development while maintaining rigorous engineering judgment and accountability for code correctness.
- Leadership: Drive team-wide best practices, conduct quality code reviews, and mentor engineers to elevate overall engineering quality.
- Collaboration: Partner with Product and Design to translate requirements into intuitive UI, making informed technical trade-offs in the face of ambiguity.
Minimum Qualifications
- Experience: 5+ years building reliable, high-performance frontend applications at scale.
- Core Stack: Expertise in React (Hooks, State Management), TypeScript, and modern tooling (Vite, Webpack).
- Testing: Proficiency with Jest, React Testing Library, and Cypress/Playwright.
- UI/UX: Proven experience building design systems or component libraries with a focus on WCAG accessibility.
- AI Literacy: Demonstrated ability to use and critically validate AI-assisted coding outputs (e.g., Claude, Copilot).
- Education: Bachelor’s in CS or equivalent practical experience.
Preferred Qualifications:
Fullstack: Experience with Ruby on Rails, Node.js, or AWS/Cloud infrastructure (Docker, Kubernetes).
Why Firstup?
Because you care - about people, the work you do, and the connections you make. Work is such a large part of life; it only makes sense to make it awesome.
If you want to engage brilliant minds in a high-growth and inclusive environment where ideas are rewarded regardless of who they come from, join us. This is a rapidly changing space so if you thrive on ambiguity, are hungry for a challenge, and have the guts to speak your mind, you could be a perfect fit.
We offer an excellent PTO program, great health benefits, a casual and friendly environment, remote work, and a leadership team who truly believes in your growth – both personally and professionally.
Firstup is committed to providing equal employment opportunities to all applicants for employment and to all employees, without regard to race, color, religion, gender, sexual orientation, gender identity or expression, national origin, age, protected disability, veteran status, or any other protected status in accordance with applicable federal, state or local laws.
#LI-TM1
#LI-Remote
Similar Jobs
Mobile • Energy • Utilities
The Senior Frontend Engineer will lead frontend development for a unified communications experience, build performant web and mobile applications, and mentor mid-level engineers while ensuring high-quality standards.
Top Skills:
Automated TestingCi/Cd ToolsGraphQLReact NativeTypescriptWeb React
Sports • Analytics
Senior Frontend Engineers at Kitman Labs build user-friendly interfaces for sports data products, focusing on usability and performance while collaborating with backend teams.
Top Skills:
ReactRuby
Fintech • Information Technology • Payments • Software
As a Senior Frontend Engineer, you'll develop seller-facing products, enhance the design system, and ensure high-quality TypeScript code delivery, while collaborating with teams.
Top Skills:
CSSReactTypescript
What you need to know about the London Tech Scene
London isn't just a hub for established businesses; it's also a nursery for innovation. Boasting one of the most recognized fintech ecosystems in Europe, attracting billions in investments each year, London's success has made it a go-to destination for startups looking to make their mark. Top U.K. companies like Hoptin, Moneybox and Marshmallow have already made the city their base — yet fintech is just the beginning. From healthtech to renewable energy to cybersecurity and beyond, the city's startups are breaking new ground across a range of industries.
