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