Senior Kotlin Developer

Grid Dynamics; Greater London; On-site; GBP 90,000 - 150,000; Full time

Benefits offered by this job

Bleeding-edge projects

Flexible schedule

Medical insurance

Sports

Corporate social events

Professional development

Well-equipped office

Job summary

Grid Dynamics in London seeks a Senior/Lead Kotlin Engineer to reengineer core trading and post-trade platforms, delivering high‑performance, cloud‑native services using Java and Kotlin while maintaining live platform stability.

You will drive event-driven design on the JVM, modernize legacy components, and work with data platforms, cross-margining, and credit financing, with a focus on testing, CI/CD and zero-downtime releases.

Qualifications

• Expert JVM Engineering with production Kotlin experience for multi-threaded, high-performance systems.
• Event-driven design including message-passing, failure handling, ordering guarantees, and replay semantics.
• TDD as a core practice with end-to-end quality ownership.
• Capital markets & post-trade domain experience (trade lifecycle, settlement, reporting).
• Iterative delivery with trunk-based development, CI/CD, and zero-downtime releases.
• Ability to analyse, refactor, and modernise large legacy systems while maintaining stability.
• Strong technical communication and autonomous working style.

Responsibilities

• Re-engineer core trading and post-trade systems to event-driven, cloud-native JVM services (Java/Kotlin).
• Modernize legacy components while preserving live platform stability.
• Build data and market-expansion platforms including cross-margining and credit financing.
• Design for event-driven systems with strong data integrity under market pressure.
• Practice TDD and shift-left testing with containerised dependencies and end-to-end quality ownership.
• Deliver iteratively using trunk-based development, CI/CD, and zero-downtime releases.
• Engage with stakeholders and upstream/downstream teams to build domain knowledge without BAs.
• Leverage AI-assisted tools for legacy analysis, test generation, and refactoring.

Skills

JVM Expertise

Java

Kotlin

Event-Driven Architecture

TDD

CI/CD

Capital Markets

Strong communication

Tools

Kubernetes/OpenShift

OpenTelemetry

ELK

Grafana

Kafka

MongoDB

SQL Server (T-SQL)

Job description

We are looking for a Senior / Lead Kotlin Engineer to join a critical initiative reengineering core trading and post‑trade platforms. You will focus on modernizing large‑scale legacy components into high‑performance, event‑driven, cloud‑native services using Java and Kotlin, all while maintaining absolute stability on a live, financially significant platform.

Responsibilities

• Re‑engineer core trading and post‑trade systems into event‑driven, cloud‑native services on the JVM (Java and Kotlin).
• Modernize legacy components while maintaining the stability of a live, financially significant platform.
• Build new data and market‑expansion platforms that underpin the programme, alongside plumbing for cross‑margining and credit financing.
• Design for the realities of event‑driven systems: failure handling, ordering guarantees, replay semantics, and data integrity under market pressure.
• Practice TDD and shift‑left testing as default, utilizing local containerised dependencies and owning quality end‑to‑end.
• Deliver iteratively using trunk‑based development, CI/CD, and frequent zero‑downtime production releases.
• Engage directly with business stakeholders and upstream/downstream teams to build domain knowledge without relying on Business Analysts.
• Leverage AI‑assisted and agentic development tools as a genuine accelerator for legacy code analysis, test generation, prototyping, and refactoring.

Requirements

• Expert JVM Engineering: Expert‑level Java expertise with production Kotlin experience (or a clear appetite to adopt it) for multi‑threaded, high‑performance enterprise systems.
• Event‑Driven Systems: Practical experience designing message‑passing and event‑sourcing architectures, including failure handling, ordering guarantees, and replay semantics.
• Strict TDD Discipline: TDD as a core engineering practice; ability to design for testability and demonstrate end‑to‑end quality ownership.
• Capital Markets & Post‑Trade Domain: Proven hands‑on experience in trading or post‑trade environments (trade lifecycle, booking, position management, cashflow calculation, settlement, wires, client reporting, and accounting principles).
• Iterative & Continuous Delivery: Proven track record with short feedback loops, trunk‑based development, CI/CD, and regular zero‑downtime production releases.
• Legacy System Refactoring: Proven ability to analyse, refactor, and modernise large‑scale legacy systems while maintaining operational stability.
• Senior Autonomy: Strong technical communication skills to contribute to design discussions, push back constructively on technical decisions, and operate with minimal supervision in complex production environments.

Nice to have

• Domain Specialties: Deep understanding of Prime Brokerage, Synthetic (Swaps), or Cash Equity operational flows.
• Regulatory & Risk Integration: Familiarity with corporate actions, regulatory reporting obligations (e.g., 871(m), EMIR, MiFID), and integrating with risk/valuation systems in an equities context.
• Database Depth: Strong SQL Server depth (T‑SQL, schema design, performance tuning) in high‑transaction environments, alongside experience with Kafka and MongoDB at scale.
• Cloud‑Native & Observability: Experience deploying on Kubernetes/OpenShift with observability using OpenTelemetry, ELK, and Grafana.
• AI‑First Workflows: Hands‑on experience with agentic coding workflows for legacy code analysis, automated test generation, and refactoring.

We offer

• Opportunity to work on bleeding‑edge projects
• Work with a highly motivated and dedicated team
• Competitive salary
• Flexible schedule
• Benefits package - medical insurance, sports
• Corporate social events
• Professional development opportunities
• Well‑equipped office

About Us

Grid Dynamics (NASDAQ: GDYN) is a leading provider of technology consulting, platform and product engineering, AI, and advanced analytics services. Fusing technical vision with business acumen, we solve the most pressing technical challenges and enable positive business outcomes for enterprise companies undergoing business transformation. A key differentiator for Grid Dynamics is our 8 years of experience and leadership in enterprise AI, supported by profound expertise and ongoing investment in data, analytics, cloud & DevOps, application modernization and customer experience. Founded in 2006, Grid Dynamics is headquartered in Silicon Valley with offices across the Americas, Europe, and India.