Java Developer (Kafka, AWS)

Quick Facts

• Fully remote
• Backend development focus: payments and merchant settlement with Java, Spring Boot, and Kafka

Description

You will develop microservices responsible for merchant payment and settlement capabilities, including balances, debits/credits, and transaction history. The work includes building payment, top-up, and refund processing and integrations with external payment providers, as well as billing and reporting integrations (e.g., REST API and Kafka, asynchronous processes). You will also help migrate legacy services to Clean/Hexagonal Architecture, write architectural documentation, and support production via on-call.

Responsibilities

• Develop microservices for prepaid merchant wallets: accounts, balances, debits/credits, and transaction history
• Build payment, top-up, and refund flows and integrate with external payment operators
• Implement billing processes and integrate with SAP
• Create and deliver merchant reports
• Design and develop REST API / Kafka integrations and asynchronous processes
• Migrate legacy services to Clean/Hexagonal Architecture
• Create ADRs and architectural documentation
• Write and maintain unit, integration, and contract tests
• Work with Helm, GitLab CI, and GitOps environments
• Participate in code reviews and estimates; support production via on-call

Requirements

• Minimum 5 years of commercial Java experience
• Strong knowledge of Java 17+ and Spring Boot
• Practical production experience with Apache Kafka
• Strong SQL knowledge, PostgreSQL, database migrations, and transaction handling
• Experience with unit and integration tests, including Testcontainers
• Knowledge of contract testing
• Practical knowledge of Clean Architecture / Hexagonal Architecture and DDD
• Experience with Docker, Kubernetes, and CI/CD
• Ability to design REST API / OpenAPI
• Knowledge of Gradle or Maven

Benefits

• Fully remote work