Develocraft is looking for a Senior Java Developer for our international client that is expanding its SaaS platforms into Australia and must meet key-account requirements to integrate Worldpay/Payrix, with full integration targeted by April 2026. Its payments division, already provides a scalable PSP-integration architecture based on adapter-style microservices to enable rapid onboarding of new payment providers
It's short term project - 4 month
Requirements:
* 4+ years of backend development with Java and Kotlin, including extensive use of Spring Boot and Spring Cloud for distributed microservices
* Solid FinTech/Payments background with knowledge of the full payment lifecycle (authorization, capture, refund, chargeback) and hands-on experience integrating external PSPs
* Proficiency in PostgreSQL, ideally AWS Aurora, and in asynchronous messaging using RabbitMQ/CloudAMQP
* Comfortable working in containerized Kubernetes environments, specifically AWS EKS
* Experience with GitHub Spec-Kit is highly valued
* English (B2-C1)
Nice to have:
* Specific prior experience integrating Worldpay or Payrix APIs
* Experience with Australian payment schemes (BECS)
Responsibilities:
* Implement the Worldpay/Payrix integration in Java or Kotlin by translating our unified internal API to the external PSP interface, applying an adapter-style design
* Develop and validate complete payment flows for Credit Card and BECS Direct Debit, covering tokenization, payment execution, refunds, and chargeback processing
* Quickly familiarize yourself with and operate within the established PSP Integration Architecture, ensuring high-quality, scalable, and testable code consistent with the Spring Boot/Spring Cloud microservice environment
* Maintain thorough specifications and documentation for all integration work using the GitHub Spec-Kit methodology
* Collaborate closely within a compact, focused micro-team and participate in daily remote check-ins via Slack and Google Meet
What we offer:
* B2B: 1,450 - 1,750 PLN net per day