Interim Senior Kotlin Engineer - £630 p/d (Inside IR35)

Contract | London (Hybrid) | Investment Banking Technology

We are seeking an experienced Interim Senior Kotlin Engineer to join a high-performing front-office engineering team delivering a next-generation cloud-native issuance platform for global capital markets.

This platform is replacing a legacy bookbuilding system used by investment banking teams worldwide and supports high-volume, real-time workflows during critical trading windows. The engineering environment is collaborative, fast-paced, and strongly aligned to Extreme Programming (XP) principles.

The Role

This is a hands-on senior engineering position focused on designing, building, and evolving backend services in Kotlin within a modern cloud-native architecture.

You will work closely with engineers, product specialists, and business stakeholders to deliver resilient, scalable solutions that support real-time issuance and allocation workflows.

The role places strong emphasis on:

• Mob programming
• Test-driven development (TDD)
• Continuous refactoring
• Collective ownership
• Incremental delivery
• Production excellence

Key Responsibilities

• Design, develop, and maintain backend services in Kotlin
• Contribute to event-driven and event-sourced platform architecture
• Collaborate within mob programming sessions as a primary delivery model
• Deliver high-quality, well-tested, maintainable code
• Support and improve production systems with strong reliability requirements
• Participate in CI/CD and SDLC practices within an enterprise environment
• Work closely with stakeholders to deliver incremental business features
• Use incidents and operational feedback to improve system resilience and design

Required Skills & Experience

• Strong commercial experience building backend services using Kotlin
• Deep understanding of event-driven and/or event-sourced architectures
• Extensive experience with XP engineering practices, including:
  • Mob programming
  • Test-driven development (TDD)
  • Continuous refactoring
  • Clean code principles
• Strong cloud engineering experience within GCP environments, including:
  • GKE and/or Cloud Run
  • Cloud SQL
  • Memorystore
  • Artifact Registry
  • Cloud Logging
  • Key Management
• Experience working within regulated or enterprise-scale environments
• Comfortable supporting high-availability production systems
• Strong communication and collaboration skills

Desirable Experience

• Experience within capital markets, trading, or real-time financial platforms
• Exposure to front-office engineering environments
• Experience working on distributed systems handling high-throughput workflows

Working Environment

You will join a collaborative engineering culture focused on:

• Sustainable delivery pace
• Shared ownership
• Continuous learning
• Engineering excellence
• Pragmatic agile delivery

This is an opportunity to work on a business-critical platform used globally within a modern cloud-native engineering environment.

***Applicants must hold current and valid UK Right to Work***