Senior Full Stack Java/Kotlin & React Engineer – Equity Prime Finance

Grid Dynamics; Greater London; On-site; GBP 110,000 - 170,000; Full time

Benefits offered by this job

Competitive salary

Flexible schedule

Benefits package - medical insurance, 

Corporate social events

Professional development opportunities

Well-equipped office

Job summary

Grid Dynamics in London is seeking a Senior Full Stack Engineer to join a multi-year transformation for a Tier 1 investment bank's Prime Finance Equities business. You will contribute across the full stack—from event-driven backend services in Java/Kotlin to modern React/TypeScript frontends and real-time data experiences.

You will work on live, business-critical systems, replacing legacy architecture with cloud-native, scalable solutions, and collaborate with senior engineers and stakeholders

Qualifications

• Strong commercial experience as a JVM engineer with expert-level Java skills.
• Kotlin experience or strong learning ability.
• Strong React and TypeScript frontend experience, production-ready.
• Experience designing event-driven systems with message-passing or event-sourcing.
• Understanding of failure handling, ordering, replay, and data consistency.
• Frontend architecture experience including complex state management (Redux).
• Experience consuming real-time data via WebSockets and APIs.
• Web security and performance awareness; TDD and multi-layer testing.
• Capital markets, trading or post-trade environment familiarity.

Responsibilities

• Build and enhance event-driven JVM services using Java and Kotlin.
• Develop modern React/TypeScript applications for financial users.
• Deliver frontend functionality for cross-margining and credit financing.
• Build real-time interfaces using WebSockets.
• Re-engineer core trading and post-trade systems into modern services.
• Modernise legacy components while maintaining live production stability.
• Design systems with failure handling, ordering guarantees and data integrity.
• Develop robust frontend architecture with state management (Redux).
• Implement secure, performant frontend apps with proper authentication.
• Practice TDD and shift-left testing across full stack (unit/integration/E2E).
• Collaborate with stakeholders and upstream/downstream teams; CI/CD and trunk-based development.
• Leverage AI-assisted tools to accelerate legacy analysis and prototyping.

Skills

Java

Kotlin

React

TypeScript

Event-driven

WebSockets

Frontend architecture

CI/CD

Testing (TDD)

Capital markets

Tools

Kafka

Solace

TIBCO EMS

SQL Server

MongoDB

S3

Job description

The Opportunity

We are partnering with a Tier 1 investment bank on a major, multi-year technology transformation within its global Prime Finance Equities business.

The Equity Accelerator programme is focused on modernising the technology backbone of the business — re-engineering core trading and post-trade systems, developing new data and market-expansion platforms, and delivering advanced client capabilities including cross-margining and credit financing.

This is a highly hands‑on engineering opportunity working within a complex, financially critical production environment. You will help replace legacy architecture with event-driven, cloud-native systems designed for institutional-grade stability, performance and scalability.

This is not a greenfield Java project. You will work on live, business-critical systems, making architectural decisions, solving complex engineering problems and collaborating with experienced engineers and stakeholders across the Prime Finance ecosystem.

Responsibilities

The Role

We are looking for a Senior Full Stack Engineer with strong JVM experience across Java/Kotlin and modern React/TypeScript.

You will be responsible for delivering functionality across the full technology stack, from event-driven backend services through to modern user-facing applications and real‑time data experiences.

The successful candidate will combine strong software engineering fundamentals with practical experience of capital markets, trading or post-trade environments.

Key Responsibilities

• Build and enhance event-driven JVM services using Java and Kotlin.
• Develop modern React/TypeScript applications for demanding financial users.
• Deliver user-facing functionality for capabilities such as cross-margining and credit financing.
• Build real-time interfaces using WebSockets.
• Re-engineer core trading and post-trade systems into modern, event-driven services.
• Modernise legacy components while maintaining stability across a live production platform.
• Design systems around failure handling, ordering guarantees, replay semantics and data integrity.
• Develop robust frontend architecture using Redux or similar state-management technologies.
• Implement secure, performant frontend applications with appropriate authentication and security controls.
• Practise TDD and shift-left testing across the full stack, including unit, integration and E2E testing.
• Work with tools such as Jest, Cypress and Playwright.
• Contribute to trunk-based development, CI/CD and frequent production releases.
• Work directly with business stakeholders and upstream/downstream engineering teams.
• Use AI-assisted and agentic development tools to accelerate legacy analysis, test generation, prototyping and refactoring.

Requirements

Essential Experience

• Strong commercial experience as a JVM engineer, with expert-level Java skills.
• Kotlin experience or a strong interest and ability to learn Kotlin.
• Strong commercial experience with React and TypeScript, including production frontend development.
• Experience designing and building event-driven systems using message-passing and/or event-sourcing patterns.
• Understanding of failure handling, message ordering, replay and data consistency.
• Strong frontend architecture experience, including complex state management such as Redux.
• Experience consuming real-time data through WebSockets and integrating with APIs.
• Strong understanding of web performance and security.
• Demonstrable TDD experience across unit, integration and E2E testing.
• Experience with testing frameworks such as Jest, Cypress or Playwright.
• Hands-on experience within or alongside a capital markets trading or post-trade environment.
• Understanding of areas such as trade lifecycle, booking, position management, cashflows, settlement, wires, client reporting and accounting.
• Experience working with CI/CD, trunk-based development and iterative delivery.
• Experience delivering frequent, zero-downtime production releases.
• Ability to operate autonomously within complex production environments and contribute to architectural decisions.

Technology Environment

Backend

Java, Kotlin, Kafka, Solace, TIBCO EMS, SQL Server, MongoDB, S3/Object Storage

Frontend

React, TypeScript, JavaScript, HTML, CSS, Redux, WebSockets

Build & Delivery

Vite, Webpack, Jenkins, Harness, CI/CD, Docker, Kubernetes, OpenShift

Observability & Security

OpenTelemetry, ELK, Grafana, token-based authentication, HashiCorp Vault, CyberArk

Ai

GitHub Copilot, agentic coding tools and modern AI models

What We’re Looking For

This role would suit an engineer who enjoys working on complex, high‑impact financial systems rather than simply delivering isolated features.

You should be comfortable taking ownership, challenging technical decisions constructively, working directly with stakeholders and understanding the business domain behind the technology.

You will need to be equally comfortable working across backend JVM services and modern frontend applications, with a strong focus on engineering quality, testing, performance and production stability.

Nice to have

Desirable Experience

Experience in any of the following would be highly beneficial:

• Prime Brokerage
• Synthetic / Swap products
• Cash Equities
• Corporate Actions
• Regulatory reporting including 871(m), EMIR and MiFID
• Risk and valuation system integration
• Modernising and refactoring large-scale legacy systems
• Frontend architecture at scale, including micro-frontends and monorepos
• Core Web Vitals and rendering performance
• CSP and frontend security hardening
• SQL Server / T-SQL
• MongoDB
• Kafka or comparable event-streaming platforms
• Kubernetes / OpenShift
• Cloud-native engineering and operational practices
• OpenTelemetry, ELK and Grafana
• AI-first or agentic development workflows

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.