Backend AI Developer (Java/Quarkus) - Hybrid Leça da Palmeira (2 days/week office)

HumanIT Digital Consulting; Matosinhos; On-site; EUR 42,000 - 54,000; Full time

Job summary

HumanIT Digital Consulting is seeking a Mid-level Backend Developer in Porto to join the engineering team. You will design, build, and maintain backend services and APIs using Java, while embracing an AI-first approach with tools like GitLab Duo and Claude Code.

The role emphasizes collaboration with QA and product teams, implementing automated tests, and delivering reliable software in a fast-paced, AI-enabled environment. Fluency in English is preferred.

Qualifications

• 4+ years of hands-on backend development experience.
• Experience with Java; Quarkus is a plus.
• Daily use of AI-assisted development tools (e.g., Copilot, Duo, Claude Code).
• Experience designing APIs and Java-based microservices for production.
• Experience writing automated unit and integration tests.
• Ability to understand the feature's business context before solving it.
• Curiosity to experiment with AI tools and integrate them responsibly.
• Comfort in a fast-moving environment with evolving AI practices.
• Strong verbal and written English skills (B1+).
• Collaborative, adaptable, and able to manage priorities.

Responsibilities

• Design, build, and maintain backend services and APIs using Java.
• Collaborate with backend engineers, QA, and product to deliver reliable software.
• Write automated unit and integration tests and participate in CI/CD tasks.
• Follow an AI-first development approach and use AI tools daily.
• Perform AI-assisted code reviews and troubleshooting within the team.

Skills

Backend development

Java

AI-assisted tools

API design

Testing (unit/integration)

Business context understanding

Curiosity & experimentation

Communication (English)

Team collaboration

CI/CD awareness

Tools

GitLab Duo

Claude Code

GitHub Copilot

Job description

ABOUT THE OPPORTUNITY

Our client, a technology-driven company shaping the future of mobility across the Iberian market, is looking for a Mid-level Backend Developer to join their engineering team. This is a chance to work at the intersection of backend engineering and applied AI, using tools like GitLab Duo and Claude Code as part of your everyday workflow to build reliable, high-quality software faster.

PROJECT & CONTEXT

You will design, build, and maintain backend services and APIs using Java and Quarkus, while embracing an AI-first approach to how the team codes, tests, and reviews software. Day-to-day work includes solving backend tasks such as features, bug fixes, refactors, and integrations, writing automated unit and integration tests, participating in AI-assisted and peer code reviews, and troubleshooting CI/CD pipelines with the help of GitLab Duo. You'll collaborate closely with backend engineers, QA, and product to deliver dependable, well-tested software in a fast-moving, AI-enabled environment.

WHAT WE'RE LOOKING FOR (Required)

• 4+ years of hands-on backend development experience
• Experience with Java (Quarkus is a plus)
• Practical experience using AI-assisted development tools such as GitHub Copilot, GitLab Duo, Claude Code, or similar as part of a daily engineering workflow
• Experience designing and building APIs and Java-based microservices that run reliably at scale in production
• Experience writing automated unit and integration tests for backend systems
• Ability to understand the functional and business context of a feature before designing the technical solution
• Curiosity and willingness to experiment with new AI tools and integrate them responsibly into day-to-day development practices
• Comfortable working in a fast-moving environment where AI-assisted development practices are still evolving
• Strong attention to detail, critical thinking, and problem-solving skills
• B1 English (Intermediate) minimum, with good verbal and written communication skills
• Collaborative, adaptable, and able to manage multiple priorities effectively

NICE TO HAVE (Preferred)

• Experience with LLM-based integrations, Retrieval-Augmented Generation (RAG), or agent orchestration workflows
• Familiarity with MCP (Model Context Protocol) or similar tool/context integrations that connect AI assistants to internal systems
• Exposure to AI-native development practices beyond code completion, such as spec-driven development frameworks, custom prompt or skill libraries, and automation workflows