Senior Full Stack Engineer - Java/Kotlin - Equity Accelerator, Prime Finance

Grid Dynamics; Greater London; On-site; GBP 90,000 - 140,000; Full time

Benefits offered by this job

Flexible schedule

Competitive salary

Medical insurance

Job summary

Grid Dynamics seeks a senior software engineer in London to help modernize a Prime Finance equities platform. You will own end-to-end development across JVM services and React/TypeScript frontends, delivering real-time data features and cloud-native re-engineering of core trading systems.

You’ll work in a complex production environment with high standards, frequent releases, and strong collaboration with business stakeholders. A background in capital markets and hands-on testing are essential.

Qualifications

• Strong JVM engineer with Java/Kotlin experience and senior-level React/TypeScript skills.
• Experience designing event-driven systems with message-passing and event-sourcing patterns.
• Solid frontend architecture with real-time data via WebSockets and robust API integration.
• Test-Driven Development across backend and frontend; ownership of quality end-to-end.
• Hands-on experience in capital markets trading or post-trade environments.

Responsibilities

• Build end-to-end features: backend JVM services (Kotlin/Java) and frontend (React/TypeScript).
• Deliver real-time data surfaces for client features like cross-margining and credit financing.
• Re-engineer trading and post-trade systems into cloud-native services while maintaining live platform stability.
• Design for failure handling, ordering guarantees, and data integrity under market pressure.
• Engage with business stakeholders and upstream/downstream teams to deepen domain knowledge.

Skills

JVM engineer

Kotlin

React

TypeScript

Event-driven systems

Redux

WebSockets

TDD

CI/CD

Autonomy

Tools

Kafka

Kubernetes/OpenShift

OpenTelemetry

ELK/Grafana

SQL Server

MongoDB

Job description

This is a chance to help rebuild the technology backbone of a global Prime Finance business.

JUXT is partnering with a Tier 1 investment bank on its Equity Accelerator program, a multi-year, high-visibility initiative to modernize the Prime Finance Equities platform. The program is re-engineering core trading systems, building brand-new data and market-expansion platforms, and launching advanced client features such as cross-margining and credit financing. Legacy architecture is being replaced with event-driven, cloud-native systems built for institutional-grade stability, throughput, and extensibility. The engineers on this team are the ones modernising systems and making things happen.

This is not a greenfield build. You’ll work directly within a complex, financially significant production system, assessing system behavior and data integrity in live market conditions, shaping architectural decisions, and operating with real autonomy alongside an experienced, high-caliber engineering group. This is not general-purpose Java delivery: the domain is deep, the standards are high, and the impact is immediate.

Responsibilities

What you’ll work on

• Building features end-to-end: event-driven JVM services (Kotlin and Java) on the backend, and modern React/TypeScript applications on the front.
• Delivering user-facing surfaces for advanced client features such as cross-margining and credit financing, including real-time data over WebSockets.
• Re-engineering core trading and post-trade systems into event-driven, cloud-native services, and modernising legacy components while keeping a live platform stable.
• Designing for the realities of event-driven systems: failure handling, ordering guarantees, replay semantics, and data integrity under market pressure.
• Frontend engineering done properly: state management (Redux), performance, security best practice (token-based auth, XSS prevention), and automated testing.
• Practising TDD and shift-left testing as the default across the whole stack. Local-first testing, fast feedback loops, and owning the quality of your deliverables end-to-end rather than handing it to a QA group.
• Delivering iteratively: trunk-based development, CI/CD, and frequent (weekly or better) production releases during business hours with no service interruption.
• Engaging directly with business stakeholders and upstream/downstream teams to build your own domain knowledge, rather than relying on Business Analysts to hold it for you.
• Using AI-assisted and agentic development tooling as a genuine accelerator for analysis of legacy code, test generation, prototyping and refactoring.

Requirements

Requirements for the candidate

Essential

• Strong JVM engineer (Java, with Kotlin experience or an interest to learn) and senior-level modern React and TypeScript, with a track record of shipping production frontends for demanding users.
• Practical experience designing and building event-driven systems on message-passing and event-sourcing patterns, including failure handling, ordering guarantees and replay semantics.
• Solid frontend architecture instincts: complex state management (Redux or similar), consuming real-time data (WebSockets), robust API integration, and web performance and security awareness.
• Test-Driven Development as a practice, not an aspiration, across both halves of the stack (unit, integration and E2E (Jest/Cypress/Playwright)). You own quality end-to-end and design for testability. This is assessed at interview.
• Hands-on experience in or alongside a capital markets trading or post-trade environment: the trade lifecycle, trade booking and position management, and post-trade operations such as cashflow calculation, settlement and wires, client reporting, and accounting principles. You should be able to back this up with concrete examples, not high-level familiarity.
• A track record in genuine iterative delivery incl. short feedback loops, trunk-based development, CI/CD, and regular zero-downtime production releases. No waterfall projects labelled as agile.
• Senior-level autonomy: you contribute to design discussions, push back constructively on technical decisions, and operate with minimal supervision in a complex production environment.

Nice to have

Highly valued but not essential

• Understanding of Prime Brokerage, Synthetic (Swap) or Cash Equity operational flows is a significant advantage.
• Familiarity with corporate actions, regulatory reporting obligations (e.g. 871(m), EMIR, MiFID), and integrating with risk/valuation systems in an equities context.
• Proven ability to analyse, refactor and modernise large-scale legacy systems while maintaining stability.
• Frontend architecture at scale: micro-frontends, monorepos, Core Web Vitals and rendering performance, CSP and security hardening.
• Strong SQL Server skills, MongoDB, and Kafka (or comparable event-streaming platforms).
• Kubernetes/OpenShift deployment and cloud-native operational practices, with observability via OpenTelemetry, ELK and Grafana.
• Demonstrated AI-first development experience: agentic coding workflows for legacy analysis, refactoring and test generation, with a clear- eyed view of where the tools help and where they don’t.

Who this role suits

This is a senior, delivery-focused engagement on a strategic multi-year programme. It suits a genuine all-rounder who is as comfortable reasoning about event ordering in a Kafka topology as about state management in a React app, is proactive about building deep domain knowledge, and holds themselves to high engineering standards without needing an external quality gate.

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.