Senior Backend Engineer

We are looking for a Backend Java Engineer to join our team and help design, develop, and maintain scalable, high-performance backend services that support critical business applications.

In this role, you will be responsible for building robust and efficient solutions, ensuring code quality, and contributing to the continuous improvement of our software development practices. You will work closely with cross-functional teams in a dynamic and international environment.

The role combines backend development, software engineering best practices, and operational excellence, with a strong focus on scalability, maintainability, and performance.

Responsibilities:

Design, develop, and maintain scalable backend services and APIs using Java frameworks such as:

• Quarkus
• Spring Boot

Ensure application reliability, performance, and scalability across all environments.

Promote and implement continuous improvement initiatives within the software development lifecycle.

Apply software engineering best practices to:

• Develop high-quality code
• Improve maintainability
• Increase development efficiency

Analyze, troubleshoot, and resolve complex application issues.

• Conduct root cause analysis
• Perform post-mortem activities to prevent recurrence

Monitor and optimize application performance and resource utilization.

Support the evolution of backend architecture and future technical decisions.

Ensure code quality through:

• Automated testing
• Peer code reviews
• Clean Code principles

Collaborate with:

• Developers
• Architects
• Product Owners
• Managers
• External stakeholders

Ensure timely delivery and alignment across distributed teams.

Participate in production support and incident resolution activities when required.

Requirements:

6+ years of experience in a Backend Software Engineering role.

Strong knowledge of Java fundamentals, including:

• Collections
• Classes
• Interfaces
• Enums
• Inheritance
• Exception handling

Hands-on experience in the design, development, and operation of scalable backend services using:

• Quarkus
• Spring Boot

Solid understanding of:

• Databases
• Transaction management
• Data persistence concepts

Experience ensuring code quality through:

• Automated testing
• Code reviews
• Clean Code principles

Strong experience in:

• Performance optimization
• Troubleshooting production environments
• Root cause analysis

Excellent problem-solving and analytical skills.

Ability to work with:

• Autonomy and ownership
• Proactivity and leadership
• Collaboration and a continuous improvement mindset

Fluent English proficiency (mandatory, minimum B2 level).

If this sounds like you, share your CV with us and let's talk!

talent.europe@99x.io

Contacts and Address

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Alameda Fernão Lopes, 16, 13º 1495-190 Lisboa • Portugal