Senior Java Backend Developer

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We are Nimber, and we are not just filling positions, we are building a team that is ready to shake things up. If you are ready to rewrite the rules and make a real impact, this is your moment. Join us and let's put the future where it belongs. In the hands of passionate people.

But what does Nimber mean?

In mathematics and game theory, they are numbers with special properties of addition and multiplication. And what we really want is to add value to customers' projects.

Position: Senior Java Backend Developer (Spring Boot)

Location: Lisbon or Porto, Portugal (Hybrid – 2 days per week at the office)

You will join the IT Payments Team, working alongside a highly collaborative team. In this role, you will play a key part in the design, development and maintenance of high-performance backend services and microservices, contributing to secure integrations and scalable solutions within the payments domain. This is an opportunity to work with modern Java and Spring Boot technologies, collaborate with international stakeholders and contribute to high-quality software architecture.

Fullstack experience with Angular will also be highly valued.

Responsibilities

• Design, develop and maintain high-performance microservices and RESTful APIs using Java and Spring Boot;
• Build scalable, secure and efficient backend solutions, following clean code principles and enterprise design patterns;
• Design and implement secure API integrations and communication between microservices and external systems;
• Collaborate with Product Owners, Tech Leads and cross-functional teams to translate business requirements within the payments domain into technical solutions;
• Ensure robust error handling, performance optimization and secure communication across services;
• Participate in code reviews and promote development standards and engineering best practices;
• Troubleshoot, debug and optimize application performance, latency and resource utilization;
• Contribute to the continuous improvement of CI/CD pipelines, supporting automated testing and deployment processes;
• Collaborate with the international team.

Requirements

• Degree in Technology, Computer Engineering or a similar field (equivalent professional experience will also be considered);
• At least 6 years of professional experience in Java development, particularly in backend and microservices architecture;
• Strong expertise in Spring Boot (3.x) and the wider Spring ecosystem, namely Spring MVC, Spring Security and Spring Data JPA;
• Solid experience with Java 17/21 and strong knowledge of object-oriented programming, design patterns and multithreading;
• Experience in RESTful API design, API-first strategies and secure microservices communication, namely OAuth2 and JWT;
• Strong knowledge of SQL databases, preferably Oracle or PostgreSQL;
• Experience with CI/CD automation tools, namely Jenkins, XL Deploy and XL Release, or similar;
• Fluency in English (minimum B2/C1 level) – mandatory;
• Availability to work from the Lisbon/Porto office 2 days per week, within a flexible hybrid model;
• Strong problem-solving, debugging and analytical skills;
• Good communication skills and ability to collaborate within an international and multicultural team.

Nice to have: Experience in frontend development using Angular, preferably with the latest versions, French language skills, knowledge of Agile methodologies such as Scrum and Kanban, familiarity with tools like Jira, and previous experience in the payments domain.

Ready to join us and succeed?

If you're tired of feeling like just a number, send us your application and become a Nimber!