Java Integration Developer (f/m/x)

Sii Poland; Warszawa; On-site; PLN 180,000 - 260,000; Full time

Job summary

Sii Poland invites a skilled Java Integration Developer to join a transformative project in the digital business domain. You will create and develop integration services and APIs, design integrations between systems, and collaborate with architects, analysts, and project teams, using Java 21+ and Spring Boot.

This role emphasizes CI/CD automation and Kubernetes environments to ensure quality, security, and performance.

Qualifications

• 4+ years of commercial Java experience with Java 21+ and Spring Boot.
• Designing and implementing system integrations and APIs (REST, JSON, OpenAPI, OAuth 2.0, JWT, SOAP, XML).
• Experience with asynchronous integrations (Kafka, RabbitMQ, or similar).
• Experience with API management platforms and API publishing & security.
• Microservices architecture and Kubernetes deployment experience.
• CI/CD knowledge (Bamboo or Jenkins) and Git/Bitbucket; deployment automation & Jira.
• Unit testing and Java testing frameworks.
• Databases: PostgreSQL or Oracle SQL; ability to create and optimize queries.
• Fluent Polish.

Responsibilities

• Design, implement, test, and maintain integration flows and APIs.
• Participate in technical decisions for integration and API implementation.
• Ensure quality, security, availability, and performance of solutions; diagnose issues.
• Collaborate with architects, analysts, Product Owners, and project teams to refine requirements.
• Participate in estimation, planning, and risk analysis.
• Support team members and share best practices.
• Conduct code reviews and promote coding quality standards.

Skills

Java development

Spring Boot

REST APIs

OpenAPI

OAuth 2.0

JWT

SOAP

XML

Asynchronous integrations

Microservices

Kubernetes

CI/CD

Git/Bitbucket

Jira

PostgreSQL

Oracle

Polish language

Problem solving

Tools

Docker

Kubernetes

Helm

Jira

Git/Bitbucket

Bamboo

Jenkins

PostgreSQL

Oracle

OpenAPI

Job description

We are looking for a skilled Java Integration Developer to join a transformative project in the digital business domain. You will be responsible for creating and developing integration services and APIs, designing and implementing integrations between systems, and collaborating with architects, analysts, and project teams. Your work will involve utilizing CI/CD automation and Kubernetes environments to ensure the quality, security, and performance of services. This role offers opportunities for further development in API management, asynchronous integrations, and orchestration. If you are passionate about systems integration and want to make an impact, this opportunity may be the right fit for you.

Your tasks

• Designing, implementing, testing, and maintaining integration flows and APIs according to requirements and Definition of Done
• Actively participating in technical decision‑making regarding integration and API implementation, considering architectural standards
• Ensuring the quality, security, availability, and performance of delivered solutions, including diagnosing issues and addressing their root causes
• Collaborating with architects, analysts, Product Owners, and project teams to refine requirements and agree on solutions
• Participating in estimation, work planning, and analysis of technical risks
• Supporting team members in solving technical problems and sharing best practices
• Regularly participating in code reviews and developing coding quality standards and software production automation

Requirements

• Minimum 4 years of commercial experience in developing applications in Java, including practical work with Java 21+ and Spring Boot
• Hands‑on experience designing and implementing system integrations and APIs using REST, JSON, OpenAPI, OAuth 2.0, JWT, SOAP, and XML
• Practical knowledge of asynchronous integrations using Apache Kafka, RabbitMQ, or another message broker
• Proficiency in implementing integrations using API Management platforms, including API publishing and security
• Background in developing solutions based on microservices architecture and deploying them in a Kubernetes environment
• Strong understanding of CI/CD processes, particularly Bamboo or Jenkins, as well as Git/Bitbucket repositories; practical experience with deployment automation and Jira
• Knowledge of unit testing and Java testing frameworks
• Solid experience with PostgreSQL or Oracle databases, including creating and optimizing SQL queries
• Ability to work independently, solve problems, and make technical decisions within projectsFluent Polish

Nice to have

• Experience working with Microsoft Azure API Management or an equivalent solution
• Practical experience with Docker, Kubernetes, and Helm
• Knowledge of Apache NiFi in integration solutions

Job no. JOB-G4BHV

Sii ensures that all hiring decisions are made solely on the basis of qualifications and competence. We are committed to equal and fair treatment of all, regardless of legally protected characteristics. At Sii, we promote a diverse and inclusive work environment, in full compliance with applicable anti-discrimination laws.