Company: Client of Xcelyst
Location: London, UK
Working Model: Hybrid – 2–3 days onsite per week
Salary: Up to £105,000 per annum
Employment Type: Fixed-Term Contract
Role Overview Our client is looking for an experienced Kotlin Developer to work on a strategic technology programme for a leading global financial-services client in London.
The successful candidate must have strong, hands-on experience in core Kotlin development and be comfortable designing, developing and supporting secure, scalable backend applications within a complex enterprise environment.
Key Responsibilities Design, develop and maintain backend applications using core Kotlin.
Produce clean, reusable, testable and maintainable code.
Develop scalable APIs, services and business components.
Participate in application design and technical architecture discussions.
Troubleshoot application, performance and production issues.
Write unit and integration tests to maintain high engineering standards.
Participate in code reviews and contribute to development best practices.
Collaborate with developers, architects, business analysts and product teams.
Work within an Agile delivery environment.
Support the continuous improvement and modernisation of existing platforms.
Essential Skills Strong commercial experience in hands-on Kotlin development.
Excellent understanding of core Kotlin concepts, including coroutines, collections, null safety and functional programming.
Strong backend development and API engineering experience.
Experience with Spring Boot or similar backend frameworks.
Good understanding of microservices and distributed application architecture.
Strong knowledge of REST APIs, databases and system integrations.
Experience with automated testing, preferably TDD.
Familiarity with CI/CD pipelines and cloud-based development environments.
Strong problem-solving and communication skills.
Experience working in Agile engineering teams.
Desirable Skills Previous experience within banking, financial services or capital markets.
Experience developing high-volume or business-critical applications.
Exposure to cloud platforms such as GCP, AWS or Azure.
Knowledge of containerisation and orchestration technologies.
Experience with event-driven systems and messaging platforms.

Interview Process The selection process consists of two stages

Virtual technical interview
In-person interview in London
Candidates must be comfortable working onsite in London for 2–3 days per week.