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TST Group

Java Software Engineer

On site

London, United kingdom

Full Time

18-03-2026

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Skills

Java JavaScript TypeScript Apache Kafka GitHub GitLab CI/CD DevOps Docker Kubernetes Monitoring Jenkins apache angular react Postman Junit Spring Spring Boot CI/CD Pipelines API Management Kafka Microservices GitHub Actions

Job Specifications

Client: Mphasis [www.mphasis.com]

Job: Java Developer

Type: Inside IR35 Contract

Location: London, UK [5 days Onsite/Week] - Mandatory

Job Description:

We are seeking a highly skilled Full Stack Developer with strong experience in Java, Spring Boot, Kafka, and API Management platforms (Apigee) to build and support scalable, secure, and high-performance applications in the payments / banking domain. The ideal candidate will have hands-on experience with PayEdge or payment processing platforms, RESTful APIs, and modern front-end technologies.

Key Responsibilities

Backend / Microservices

Design, develop, and maintain Java-based microservices using Spring Boot
Implement RESTful APIs and integrate with internal and external systems
Build event-driven architectures using Apache Kafka (producers, consumers, streams)
Ensure high availability, scalability, and performance of services
Implement security using OAuth2, JWT, API keys, and role-based access

API Management & Integration

Design, publish, and manage APIs using API Gateway / Apigee
Configure API policies (security, throttling, caching, monitoring, transformation)
Manage API lifecycle, versioning, and documentation
Integrate APIs with PayEdge / payment gateways / core banking systems

Frontend / Full Stack

Develop responsive UI components using Angular / React / JavaScript / TypeScript
Integrate front-end applications with backend APIs
Ensure cross-browser compatibility and performance optimization

Payments / Banking Domain

Work on payment processing flows, transaction orchestration, and reconciliation
Support integrations with PayEdge, ACH, RTP, wire, or card-based payment systems
Ensure compliance with PCI-DSS, SOX, and regulatory standards

DevOps & Quality

Write unit, integration, and API tests (JUnit, Mockito, Postman)
Support CI/CD pipelines using Jenkins / GitHub Actions / GitLab
Containerize applications using Docker and deploy to Kubernetes / Cloud
Monitor and troubleshoot production issues

About the Company

TST Group is one of the UK/Europe’s leading recruitment firm. Our comprehensive range of talent solutions are backed by our deep understanding of our client needs and rich industry experience. Headquartered in Warsaw, Poland our vast global presence and unyielding customer centricity have enabled us to forge strategic partnerships with leading Fortune 500 companies, worldwide. In an international marketplace in which effectiveness and value are increasingly prized by both clients and candidates, we believe that the qualiti... Know more