Senior Full Stack (Java/Kotlin/React/TS) Engineer

JUXT; Greater London; On-site; GBP 110,000 - 150,000; Full time

Job summary

JUXT is partnering with a Tier 1 investment bank on a major transformation of its Prime Finance Equities platform. You will build Java/Kotlin event‑driven services and modern React/TypeScript applications within an live, financially critical environment.

The role focuses on modernising legacy trading/post-trade systems, ensuring data integrity, and embracing cloud-native tech with Kubernetes/OpenShift, Kafka, and CI/CD pipelines. Prior fintech experience is a plus.

Qualifications

• Senior-level autonomy and strong architectural instincts.
• Experience with capital markets, trading or post-trade.
• Experience with iterative delivery and trunk-based development.

Responsibilities

• Build Java/Kotlin event-driven services and modern React/TypeScript applications.
• Modernise complex legacy trading and post-trade systems.
• Design for failure handling, ordering, replay and data integrity.
• Apply TDD across unit, integration and E2E testing.
• Work with Kafka, Solace, TIBCO EMS, SQL Server&MongoDB.
• Build and deploy using Docker, Kubernetes/OpenShift&CI/CD.
• Work with OpenTelemetry, ELK&Grafana.
• Use AI-assisted/agentic coding tools for legacy analysis, testing and refactoring.
• Kotlin experience or willingness to learn.
• Event-driven / message-passing / event-sourcing experience.
• Redux, WebSockets and API integration.
• Genuine hands‑on TDD experience.
• Background in capital markets, trading or post-trade.
• Experience with iterative delivery, trunk-based development and CI/CD.

Skills

Java/Kotlin

React/TypeScript

Event-driven

TDD

CI/CD

Kafka

OpenTelemetry

ELK

Grafana

AI-assisted coding tools

Tools

SQL Server

MongoDB

Docker

Kubernetes/OpenShift

CI/CD

Job description

Senior Full Stack Engineer – Java/Kotlin&React

We are partnering with a Tier 1 investment bank on a major, multi-year transformation of its Prime Finance Equities platform.

The Equity Accelerator programme is re-engineering core trading and post-trade systems, replacing legacy architecture with modern event-driven, cloud-native technology and delivering advanced capabilities includingcross-margining and credit financing.

This is a genuine engineering role working on live, financially critical systems— not a greenfield project or generic Java delivery.

What you'll be doing

• Build Java/Kotlin event-driven services and modern React/TypeScript applications
• Modernise complex legacy trading and post-trade systems
• Design for failure handling, ordering, replay and data integrity
• Apply TDD across unit, integration and E2E testing
• Work with Kafka, Solace, TIBCO EMS, SQL Server&MongoDB
• Build and deploy using Docker, Kubernetes/OpenShift&CI/CD
• Work with OpenTelemetry, ELK&Grafana
• Use AI-assisted/agentic coding toolsfor legacy analysis, testing and refactoring
• Kotlin experience or willingness to learn
• Event-driven / message-passing / event-sourcing experience
• Redux, WebSockets and API integration
• Genuine hands‑on TDD experience
• Background in capital markets, trading or post-trade
• Experience with iterative delivery, trunk-based development and CI/CD
• Senior-level autonomy and strong architectural instincts

Prime Brokerage, Synthetic/Swap or Cash Equities experience, plus exposure to Corporate Actions, 871(m), EMIR, MiFID, Kafka, SQL Server, Kubernetes/OpenShift or cloud-native platforms.

*We cannot offer sponsorship for this role*