Java backend developer for checkout systems

We are looking for a Junior Java Backend Developer to join a collaborative engineering team working on the evolution of digital products such as Checkout, MyAccount, and ODR Processing. You will develop and maintain Java microservices, build and integrate APIs, contribute to automated testing and CI/CD quality gates, and gain exposure to modern Identity & Access Management technologies. This is an excellent opportunity for an early-career developer who wants to strengthen their backend engineering skills while learning from senior engineers and participating in a structured technical upskilling programme.

• Develop and maintain Java-based microservices.
• Build and integrate RESTful and GraphQL APIs.
• Write unit and integration tests.
• Contribute to code quality and security practices.
• Support IAM integrations using modern authentication technologies.
• Participate actively in Agile development.
• Continuously expand your technical skills through mentoring and structured training.
• Implement new functionalities for Checkout, MyAccount, and ODR Processing solutions.
• Work alongside senior engineers to understand technical requirements and solution designs.
• Write clean, maintainable, and testable code.
• Follow established software engineering and coding standards.
• Troubleshoot application issues and contribute to technical improvements.
• Design and implement RESTful APIs according to established standards.
• Contribute to GraphQL API development and integration.
• Follow OpenAPI documentation standards.
• Implement reliable integrations between backend applications and services.
• Support API testing and troubleshooting.
• Develop and maintain unit tests and integration tests.
• Contribute to automated quality gates.
• Identify code quality and security issues.
• Support the continuous improvement of test coverage and application reliability.
• Support the integration of authentication and authorization flows.
• Work with senior engineers to implement secure authentication mechanisms.
• Follow established security guidelines and IAM standards.
• Work with GitLab-based development workflows.

• Approximately 2 years of professional software development experience.
• Professional experience with Java development.
• Good understanding of backend development principles.
• Knowledge of microservices concepts.
• Familiarity with REST APIs.
• Understanding of automated testing principles.
• Experience or familiarity with Git-based development workflows.
• Strong willingness to learn and develop technically.
• Ability to collaborate effectively within a team.
• Portuguese C1.
• English C1.
• Strong learning mindset and curiosity.
• Good analytical and problem-solving capabilities.
• Team-oriented and collaborative attitude.
• Openness to technical feedback and mentoring.
• Attention to code quality and security.
• Proactive approach to personal and technical development.
• Clear communication in both Portuguese and English.

• Develop modern Java microservices within an enterprise environment.
• Gain practical experience with REST and GraphQL APIs.
• Work with modern IAM technologies such as Keycloak, Okta, and OIDC.
• Strengthen your knowledge of code quality and application security through SonarQube and Snyk.
• Receive guidance from senior engineers.
• Participate in a structured technical upskilling programme.
• Build a strong foundation for progression toward a Mid-Level Backend Engineer position.