We are seeking an experienced Postilion Java Developer to design, develop, and support mission-critical payment switching applications. The role requires strong hands-on expertise in Postilion development combined with Java and Spring Boot, along with a solid understanding of card payment authorization flows, ISO 8583 messaging, and payment scheme integrations.

The successful candidate will contribute to real-time transaction processing, system integrations, scheme compliance, and performance optimisation across high-volume payment environments while supporting the modernisation of legacy switching platforms.

Key Responsibilities

• Design, develop, and maintain Postilion-based payment switching applications supporting real-time transaction processing.
• Develop and customise Postilion components using Realtime Developer tools, eSocket integrations, ATMApp development, and Postilion configuration scripting.
• Implement payment flows including PIN debit, EMV transactions, contactless payments, authorisations, reversals, settlements, and dispute processing.
• Configure and manage ISO 8583 message mappings, BIN routing, transaction logic, and scheme rule implementations.
• Integrate Postilion switching platforms with Java/Spring Boot microservices and external APIs.
• Perform impact analysis and implementation of Visa, Mastercard, eftpos, and other scheme rule changes.
• Support PCI-DSS compliance requirements, scheme certification testing, and security best practices.
• Provide L2/L3 production support, troubleshooting transaction failures, system performance issues, and operational incidents.
• Participate in 24/7 on-call support rotations where required.
• Contribute to legacy system modernisation initiatives, integrating Postilion with microservices and modern digital payment channels.
• Implement performance optimisation, monitoring, logging, and automation for high-volume transaction processing environments.
• Collaborate with architecture, infrastructure, and operations teams to ensure scalability, reliability, and operational efficiency.

Required Skills & Experience

• Strong hands-on experience with Java (11+) and Spring Boot development.
• Extensive experience working with Postilion Realtime platform, including eSocket, ATMApp, and Postilion configurations.
• Solid understanding of ISO 8583 messaging standards and real-time payment transaction processing.
• Experience with payment switching environments supporting acquiring or issuing platforms.
• Knowledge of card scheme processing including authorisation, clearing, settlement, chargebacks, and reversals.
• Experience working with EMV, contactless payments, tokenisation, and fraud detection processes.
• Familiarity with message streaming and integration technologies such as Kafka or RabbitMQ.
• Experience with databases such as Oracle or PostgreSQL.
• Exposure to cloud and DevOps technologies including AWS, Docker, Kubernetes, Jenkins, and Git.
• Experience supporting high-availability, high-volume transaction systems.

Preferred Experience

• Experience working with Visa, Mastercard, or eftpos scheme integrations and certification processes.
• Experience with PCI-DSS compliant environments and secure payment application development.
• Exposure to containerised deployments and CI/CD pipelines.
• Experience with monitoring and observability tools such as Splunk.

No work visa sponsorship available. Due to the volume of applications, only shortlisted candidates will be contacted.