Senior Kotlin Engineer (Event Streaming/Sourcing) – London

Senior Kotlin Software Engineer (Investment Banking) – London/hybrid Daily rate: £600 – £1000 Duration: 6 months Hybrid: 2 days on site Start: ASAP My banking client is looking for 2 experienced Senior Kotlin Software Engineers to join a cloud-hosted platform team within an investment banking environment. This is a fast-paced, front-office-facing role with a strong emphasis on high-quality engineering, reliability, and collaborative working practices.
The role offers exposure to modern engineering practices and the opportunity to work closely with business stakeholders in a demanding and high-impact environment.
Key Responsibilities Design, develop, test, and maintain backend services using Kotlin
Contribute across the full software lifecycle: development, integration, and production support
Implement and support event-driven architectures, including event sourcing and event streaming
Work within an Agile/XP environment, utilising: Pair programming
Mob programming
Test-first development practices Build and maintain CI/CD pipelines and deploy services to cloud environments
Continuously refactor code and uphold high standards of code quality and reliability
Participate in architectural and technical design discussions
Collaborate closely with front office stakeholders and cross-functional teams
Deliver solutions within short timelines and respond to urgent business needs Essential Skills & Experience Strong commercial experience developing production-grade Kotlin applications (non-Android)
Proven experience with Test-Driven Development (TDD) and test-first approaches
Hands-on experience with event-driven systems (event streaming and/or event sourcing)
Experience with CI/CD tools and practices
Strong background in refactoring legacy code and maintaining clean, maintainable systems
Experience working in Agile/XP environments, ideally including mob programming
Excellent communication skills with the ability to engage effectively with business/front office stakeholders Desirable Skills & Experience Prior experience in investment banking or financial services, particularly front office systems
Experience with cloud platforms (AWS, GCP, or Azure)
Familiarity with containerisation technologies (Docker, Kubernetes)
Experience with Kafka or similar messaging/event platforms
Understanding of distributed systems design and immutable event patterns
Experience with observability, monitoring, and incident response tools
Exposure to low-latency or high-availability systems *Rates depend on experience and client requirements