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

JUXT; Greater London; On-site; GBP 95,000 - 130,000; 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 engineer live, financially critical systems using Java/Kotlin and React/TypeScript, delivering modern, cloud-native solutions with event-driven architecture.

You will design for failure handling, data integrity, and scalable delivery, applying TDD across unit, integration, and E2E tests, and working with Kafka, SQL Server, MongoDB, Docker, Kubernetes/OpenShift, and CI/CD

Qualifications

• Experience delivering live, financially critical trading/post-trade systems.

Responsibilities

• Build Java/Kotlin event-driven services and modern React/TypeScript applications.

Skills

Java/Kotlin

React/TypeScript

Event-driven architecture

TDD

Capital markets/trading experience

Architectural instincts

CI/CD

Kafka-based systems

Tools

Java

Kotlin

React

TypeScript

Kafka

Solace

TIBCO EMS

SQL Server

MongoDB

Docker

Kubernetes

OpenShift

CI/CD tooling

OpenTelemetry

ELK

Grafana

Redux

WebSockets

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*