Senior Java Developer - Payments

VASS UK&I; Greater London; On-site; GBP 90,000 - 130,000; Part time

Job summary

VASS UK&I in London is seeking an experienced Senior Java Software Engineer to join a team developing and supporting modern payment-processing systems. This six-month contract role focuses on building secure, scalable backend applications with Java, Spring Boot, and microservices.

You will connect systems via APIs and messaging, monitor performance, resolve complex issues, and promote engineering best practices while delivering reliable production-ready solutions.

Qualifications

• Five+ years of software development experience using Java
• Experience with Spring Boot and microservices
• Experience with messaging systems like Kafka and RabbitMQ/IBM MQ
• Experience integrating APIs using REST and GraphQL
• Knowledge of relational and non-relational databases
• Strong analytical and logical reasoning skills
• Proactive approach and ability to learn quickly
• Bachelor's degree in a related field such as systems/engineering, math or tech
• Knowledge of UK/international payment standards (ISO 20022, SWIFT, MX)
• Experience with Docker and Kubernetes
• Knowledge of AWS or another cloud platform
• Experience with performance-testing tools (Gatling or JMeter)
• Familiarity with Jira and Confluence
• DevOps/CI using Gradle, GitHub Actions, Sonar

Responsibilities

• Developing and maintaining payment systems and platform services
• Building microservices, middleware applications, orchestrators, and automated tests
• Integrating systems through APIs and messaging technologies
• Providing technical guidance and promoting software engineering best practices
• Overseeing application monitoring and supporting production implementations
• Providing third-line support for complex application issues
• Improving application performance, observability, and resilience
• Working proactively within an agile development environment

Skills

Java

Spring Boot

Microservices

REST

GraphQL

Databases (SQL/NoSQL)

Analytical thinking

Proactive learner

Jira/Confluence

CI/CD (Gradle/GitHub Actions/Sonar)

Education

Bachelor's degree in Systems/Computer Engineering or related

Tools

Kafka

RabbitMQ

Docker

Kubernetes

AWS

Gradle

GitHub Actions

Sonar

Gatling

JMeter

Jira

Confluence

Job description

Imagine working alongside over 4,000 talented individuals driven by a shared passion for excellence and innovation. We’re not just a company; we are a dynamic ecosystem of companies, including VASS, NATEEVO, Serbatic, vdSHOP, T4S, Comunytek, ECENTA, and CRI group. Our collective strength and the E4 Agile Method empower us to assist large enterprises in their digital transformation journey, executing ground-breaking projects from strategy to operation.

Global Impact, Local Commitment:

At VASS we are not just a business; we are committed to society. In 2019, we established the VASS Foundation to champion research and training in the digital talent space. We proudly allocate 2% of our profits and encourage our entire team to dedicate 1% of their time to impactful solidarity actions. It is not just about growing the bottom line; it’s about growing together, hand in hand with the community we serve.

About the role:

We are seeking an experienced Senior Java Software Engineer to join a team developing and supporting modern payment-processing systems. This position is offered initially as a six-month contract on a contractor basis.

You will build secure, reliable, and high-performing backend applications using Java, Spring Boot, and microservices.

The role involves connecting different systems through APIs and messaging technologies, monitoring application performance, resolving complex technical issues, and helping the wider development team follow software engineering best practices.

What you’ll be doing:

• Developing and maintaining payment systems and platform services
• Building microservices, middleware applications, orchestrators, and automated tests
• Integrating systems through APIs and messaging technologies
• Providing technical guidance and promoting software engineering best practices
• Overseeing application monitoring and supporting production implementations
• Providing third-line support for complex application issues
• Improving application performance, observability, and resilience
• Working proactively within an agile development environment

What we’re looking for:

• At least five years of software development experience using Java
• Experience with Spring Boot and microservices
• Experience with messaging systems—ideally Kafka and another technology such as RabbitMQ or IBM MQ
• Experience integrating APIs using REST and GraphQL
• Knowledge of relational and non-relational databases
• Strong analytical and logical reasoning skills
• A proactive approach and the ability to learn quickly
• A completed bachelor’s degree in systems engineering, computer engineering, mathematics, physics, economics, business administration, or a related discipline
• Knowledge of UK or international payment standards, including ISO 20022, SWIFT, and MX messaging
• Experience with Docker and Kubernetes
• Knowledge of AWS or another cloud platform
• Experience with performance-testing tools such as Gatling or JMeter
• Familiarity with Jira and Confluence
• DevOps and continuous-integration experience using tools such as Gradle, GitHub Actions, and Sonar

VASS is an Equal Opportunity Employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. Employment decisions are based on qualifications, merit, and business needs, without regard to race, religion, colour, sex, gender identity, sexual orientation, age, national origin, marital status, or disability status. Join us in shaping the future of digital transformation.