Senior Scala Developer (m/f/d) - Upgrade Project

We are currently looking for a freelance Senior Scala Developer (m/f/d) - Upgrade Project for our client in the Energy sector

Start: ASAP

End: 30.09.2026

Capacity: 4 days/week

Location: remote/once a month Düsseldorf

We are looking for a highly experienced Scala expert to independently drive a critical version upgrade project. The main objective is to migrate an existing codebase from Scala 2.12 to Scala 3 while ensuring high code quality and system stability. The role requires a senior developer who is comfortable working autonomously, shaping technical solutions without close supervision, and collaborating directly with stakeholders.

Tasks:

• Lead and execute the upgrade from Scala 2.12 to Scala 3
• Analyze existing code and refactor where necessary to ensure compatibility with Scala 3
• Maintain and improve code quality across repositories
• Adjust and upgrade dependent libraries in line with security and compatibility requirements
• Work independently without a traditional on-site development team
• Act as a technical sparring partner for the project manager
• Ensure smooth integration within a containerized environment

Must-have:

• Expert-level Scala experience, especially with migrations from Scala 2.x to 3.x
• Strong Java knowledge, ideally with experience in version upgrades
• Git (mandatory)
• Maven (actively used in the project)
• Solid understanding of build and dependency management

Nice-to-have:

• Experience with sbt
• Familiarity with Azure Pipelines or similar CI/CD tools
• Experience working in cloud environments (AWS or Azure)
• Knowledge of containerized systems (eg, Docker/Kubernetes)
• Exposure to security tools or vulnerability scanning processes