Senior Full Stack Engineer (£90,000-£120,000) - FinTech - Hybrid

Senior Full Stack Engineer – FinTech - Hybrid (1-2 days in London office)About the RoleWe’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 DoDesign, 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 & ExperienceEssentialSignificant commercial experience building modern web and backend applications.Strong experience with:Next.jsTypeScript / Node.jsPostgreSQLAWSKubernetesExperience 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.DesirableExperience 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 ForDesigns 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.