Principal Engineer -  Payments Platform Modernisation

Start: July 2026
Duration: Initial contract until Dec 2026, with extension potential
Location: London / Hybrid2 days onsite
Rate: Up to £850 per day Inside IR35

We are supporting a major UK financial services client on a large-scale payments modernisation initiative and are seeking experienced Software Engineers across multiple seniority levels to join a growing delivery team. This is a confidential engagement focused on the transformation of core payment gateway capabilities, API platforms, developer experience, and in-person payments infrastructure.

Responsibilities

  • Develop next-generation payment gateway capabilities
  • Support API and orchestration platform development
  • Collaborate across discovery and delivery phases
  • Architectural leadership
  • Payments subject matter expertise
  • Technical direction across the programme


Key Skills

Essential
  • Payment gateway/platform experience
  • Kotlin & Java
  • API-layer development
  • Financial services experience
Desirable
  • TypeScript