Senior Backend Developer

Senior Backend Software Engineer - FinTech

£120,000 + Share Options & Benefits Flexible office policy | South London

Tech Stack: Node.js · TypeScript · AWS · Kubernetes · REST APIs

I’m partnering with a high-growth UK payments fintech that’s fundamentally rethinking how merchants and consumers pay for goods and services.

This isn’t a company doing incremental work, they’re building genuinely disruptive infrastructure at scale, and they’re now bringing on multiple Senior Engineers to help define the next chapter of growth.

The Engineering Environment

A modern, cloud-native platform engineered for serious scale:

• Node.js, TypeScript
• React (frontend)
• AWS cloud infrastructure
• Kubernetes
• Terraform (Infrastructure as Code)

Architecture Highlights

• Event-driven, distributed systems (EventBridge, SQS)
• Public-facing REST APIs
• Fully automated CI/CD pipelines
• Data science and ML-driven personalisation
• Scalable B2B payments infrastructure

The Role

As a Senior Software Engineer, you’ll be working be shaping architecture, not just implementing it:

• Lead the design and evolution of B2B APIs and payments infrastructure
• Contribute to architectural decisions across distributed systems
• Partner with Product and UX during discovery and solution design
• Own features end-to-end, from concept through to production
• Mentor engineers and raise the bar on engineering standards
• Champion best practices across testing, CI/CD, and security

What They’re Looking For

• 8+ years in software engineering, with at least 2 years in financial services (payments, banking, or wealth) or a high-volume transaction environment (eCommerce, gaming, betting, or streaming)
• Strong backend engineering experience with Node.js and TypeScript
• A track record of building and maintaining public REST APIs
• Solid AWS experience (Terraform a plus; Kubernetes a strong bonus)
• Comfort working within distributed, event-driven architectures
• A delivery-focused mindset as you take ownership and see things through
• At ease in fast-moving, scale-up environments where ambiguity is the norm