Senior Kotlin

About the Position

The client is building the bank of the future with cutting-edge technologies. Backend Java/Kotlin engineers work in small, agile, cross-functional teams that tackle real-world problems and interact closely with stakeholders and key business users. They design, develop, and maintain high-quality backend services using Kotlin. The working schedule is aligned with the UK time zone (9am to 5:30pm UK time) and involves participating in on call shifts if required.

About the Project

The client is building the bank of the future with cutting-edge technologies. Backend Java/Kotlin engineers work in small, agile, cross-functional teams that tackle real-world problems and interact closely with stakeholders and key business users. They design, develop, and maintain high-quality backend services using Kotlin.

Responsibilities

• Design, develop, and maintain high-quality backend services using Kotlin under established patterns.
• Work closely with cross-functional teams; own architectural decision-making and complex feature delivery using coroutines and existing frameworks.
• Define testing strategy for features or services, improve test design across the squad, identify gaps in coverage or reliability, and ensure new work meets agreed quality standards (JUnit, Kotest).
• Conduct thorough and high-quality code reviews, improving team-wide code standards.
• Participate in the full software development lifecycle, from concept and design to testing and deployment; ensure production readiness and stability, owning monitoring and incident response.
• Engage in continuous improvement practices and agile methodologies; shape technical direction, raise standards, and influence architectural choices.
• Mentor and support other engineers; lead technical discussions.
• Embrace effective agentic coding practices and actively leverage AI tools such as Claude Code and Copilot.

Requirements

• 2+ years in writing production Kotlin code and implementing features using coroutines.
• Experience working on commercial, established products used by real customers, and operating software in production.
• Strong knowledge of testing strategies with tools like JUnit or Kotest; able to define and improve squad-wide test coverage.
• Backgrounds where quality, testing, and maintainability were prioritised alongside delivery, even under time or commercial pressure.
• Experience making architectural trade-offs (e.g. consistency vs availability, sync vs async) and being accountable for the long-term maintainability of those decisions.
• Deep understanding of relational database schema design, indexing, performance optimization, and migration integrity.
• Advanced Git skills including branching strategy enforcement and complex merge resolution.
• Proficient in Docker and Kubernetes deployment patterns, troubleshooting, and platform-level reliability improvements.
• Strong command of English in both oral and written communication; ability to lead technical discussions.
• Proactive risk management and structured problem-solving mindset.
• Effective team player with the ability to work independently; supports and mentors others.
• Ownership of complex or ambiguous initiatives end-to-end.

Nice to Have

• Strong experience with Kafka and event-driven architectures; comfortable with advanced patterns (dead letter queues, schema evolution, exactly once semantics).
• AWS Experience.
• Understanding event-driven patterns and async messaging (pub/sub, message queues); experience consuming or producing messages in at least one messaging platform.
• Openness to define and optimize test and deployment pipelines.
• Time spent working across multiple teams, products, or problem spaces, helping to build adaptability
• Evidence of evolving practices, responsibilities, or environments over time rather than working in one project
• Experience in organisations where engineers were embedded in teams, accountable for outcomes, and closely aligned with product and delivery goals