Senior Java Backend Engineer - Payments & AI-Driven Spec

Thrive IT Systems; Warszawa; Hybrid; PLN 180,000 - 320,000; Full time

Job summary

Thrive IT Systems in Poland is seeking a Senior Java Backend Developer with payments domain experience to design and build secure, high-performance payment services. You will be expert in Core Java, Spring Boot microservices and Kafka, and will apply AI-assisted spec-driven development to deliver quality software.

You'll work directly with Nordic client stakeholders in a hybrid setup (Gdynia and Warsaw), owning solutions from specification through to production while mentoring peers in modern

Qualifications

• Must have extensive Java backend experience, with payments domain
• Proficient in Spring Boot, microservices, and Kafka
• Experience with AI-assisted engineering and spec-driven development
• Strong API design using OpenAPI/Swagger
• Knowledge of ISO 20022, SWIFT, SEPA and real-time payment schemes
• Experience in Agile SAFe environments

Responsibilities

• Design, develop, and maintain scalable payment microservices
• Build and manage high-throughput event-driven flows using Kafka
• Write specifications and acceptance criteria to drive AI-assisted design
• Review AI-generated output for security and correctness
• Design REST APIs contract-first using OpenAPI
• Ensure banking-grade security and data protection
• Collaborate with product owners, architects, and testers in SAFe teams; mentor others
• Support production and analyze incidents in payment systems

Skills

Core Java

Spring Boot

Microservices

Kafka

OpenAPI

OAuth2/OIDC

Security

Data modeling

AI-assisted development

SAFe Agile

Tools

Docker

Kubernetes

Git

Maven

CI/CD

OpenShift

GitHub Actions

Nexus

Ansible

Job description

Thrive IT Systems in Poland is seeking a Senior Java Backend Developer with payments domain experience to design and build secure, high-performance payment services. You will be expert in Core Java, Spring Boot microservices and Kafka, and will apply AI-assisted spec-driven development to deliver quality software.

You'll work directly with Nordic client stakeholders in a hybrid setup (Gdynia and Warsaw), owning solutions from specification through to production while mentoring peers in modern