Senior Java Backend Developer - Payments & AI-Driven APIs

LTM; Gdynia; Hybrid; PLN 180,000 - 300,000; Full time

Job summary

LTM in Poland seeks a Senior Java Backend Developer with payments experience to design and build secure, high-performance payment services, leveraging Core Java, Spring Boot, microservices, and Kafka in a hybrid setup between Gdynia and Warsaw.

You will drive AI-assisted spec-driven development, turn specifications into plans, code, and tests, and own solutions from spec through production while collaborating with Nordic client stakeholders in an Agile SAFe environment.

Qualifications

• 10 years in Java backend development
• 5 years in payments or banking
• Hands-on experience with payments domain including ISO 20022 messaging and real-time schemes

Responsibilities

• Design, develop and maintain scalable payment microservices for initiation, clearing, settlement, and reconciliation
• Build event-driven flows using Kafka with idempotency, exactly-once processing, retries, and error handling
• Write specifications, requirements, acceptance criteria, API contracts, data models and use them as the source of truth for AI-assisted design, code, and tests
• Use AI coding assistants to turn specs into plans, tasks, code and tests; review AI outputs for quality and security
• Design REST APIs contract-first using OpenAPI and keep specs and code in sync
• Ensure banking-grade security, resilience, auditability, and data protection
• Mentor peers on modern Java and AI-assisted engineering; work in Agile SAFe teams
• Support production and analyze incidents for business-critical payment systems

Skills

Core Java

Spring Boot

Microservices

Kafka

AI-assisted engineering

OpenAPI

Security

Agile SAFe

Tools

Docker

Kubernetes

GitHub Copilot

OpenAPI/Swagger

Maven

Job description

LTM in Poland seeks a Senior Java Backend Developer with payments experience to design and build secure, high-performance payment services, leveraging Core Java, Spring Boot, microservices, and Kafka in a hybrid setup between Gdynia and Warsaw.

You will drive AI-assisted spec-driven development, turn specifications into plans, code, and tests, and own solutions from spec through production while collaborating with Nordic client stakeholders in an Agile SAFe environment.