Full job descriptionSenior Kotlin Engineer (XP, GCP) - Investment Banking - London/Hybrid
Daily rate: £600 - £800 (inside IR35)
Duration: 6 months
Start: ASAP


My client is looking for an experienced Senior Kotlin engineer to support and extend a cloud-hosted platform used for bookbuilding issuances within Investment Banking Capital Markets. You will join a high-calibre London-based front office engineering team working on a next-generation issuance platform replacing a legacy bookbuilding system.
This is a hands-on engineering role with a strong emphasis on Extreme Programming (XP) practices, including mob programming, test-driven development, and continuous refactoring. Engineers are expected to contribute across development, integration, and production support, collaborating closely to maintain high standards of code quality, system reliability, and performance.


Required & Desirable Skills
*Strong commercial experience building backend services using Kotlin
*Experience with event-sourced and event-driven architectures
*Deep familiarity with XP practices, including:
*Mob programming as a primary way of working
*Test-driven development (TDD)
*Continuous refactoring and clean code principles
*Cloud experience with GCP, including:
*GKE and/or Cloud Run
*Cloud SQL and Memory store
*Artifact Registry and Cloud Logging
*Key Management
*Experience with CI/CD and SDLC in regulated or enterprise environments
*Comfortable working on production systems requiring high availability and accuracy


Engineers in this role:
*Work primarily in mobs, sharing ownership of design and code
*Build, test, and evolve services with a strong focus on clarity, simplicity, and maintainability
*Support the platform in production, using incidents and defects as opportunities to improve system design and resilience
*Rates depend on experience and client requirements