Senior Full Stack Engineer – FinTech - Hybrid (1-2 days in London office)

About the Role

We’re looking for a Senior Full Stack Engineer to help build and evolve a modern FinTech platform.

This is a hands-on engineering role where you’ll design, build and operate distributed systems that process complex financial data at scale.

You’ll work across the full technology stack, integrating with third-party platforms, cloud services and open-source technologies to deliver resilient, secure and scalable software.

Working on a hybrid basis, you’ll collaborate closely with engineering, product and other teams while taking significant ownership of technical design and delivery.

What You’ll Do

• Design, build and maintain distributed web applications and backend services.
• Develop features across frontend, backend, APIs and infrastructure.
• Integrate with third-party vendor platforms, financial systems and open-source technologies.
• Design scalable APIs and data models.
• Build and operate cloud-native services on AWS and Kubernetes.
• Drive software quality through testing, observability and operational excellence.
• Contribute to architectural decisions while remaining actively involved in implementation.
• Review code, mentor engineers and help raise engineering standards.
• Troubleshoot production issues and improve system reliability and performance.
• Work closely with engineering and product teams to deliver high-quality solutions.

Skills & Experience

Essential

• Significant commercial experience building modern web and backend applications.
• Strong experience with:
• Next.js
• TypeScript / Node.js
• PostgreSQL
• AWS
• Kubernetes
• Experience designing and operating distributed systems.
• Experience integrating with third-party APIs, commercial SaaS products and open-source technologies.
• Strong understanding of REST APIs, authentication and application security.
• Experience with CI/CD and modern software delivery practices.
• Experience using AI-assisted software development tools.

Desirable

• Experience working within FinTech, financial services, capital markets or another regulated industry.
• Experience building platforms that process complex or high-volume financial data.
• Experience with event-driven architectures.
• Experience with Infrastructure as Code.
• Experience working with highly available, secure and scalable systems.

What We’re Looking For

• Designs scalable, maintainable systems and makes sound architectural decisions.
• Takes ownership from design through to production, with a strong operational mindset.
• Is comfortable working across multiple languages, frameworks and technology stacks.
• Quickly understands unfamiliar codebases and third-party systems.
• Makes pragmatic engineering decisions that balance quality, speed and long-term maintainability.
• Builds secure, reliable software by default.
• Writes clean, well-tested and maintainable code.
• Enjoys solving complex technical problems.
• Communicates effectively and collaborates well across engineering and product teams.
• Is comfortable working within a collaborative hybrid environment.