Fullstack Developer - Java

Fullstack Developer Java/Kotlin

• Workload: 80-100%
• Duration: 11.2026 to 15.11.2031, 5 years
• Latest Start date: 01.12.2026
• Location: Bern (hybrid, 2 times onsite/weekly)
• Contract type: Personnel Leasing / Personalverleih (Staff Augmentation)

Role Overview The customer is seeking a Senior Java/Kotlin Engineer to contribute to the modernization of core government platforms. The focus lies on backend development, event-driven architectures, domain-driven design and scalable distributed systems. The selected consultant will work within Agile Scrum teams and contribute to highly critical applications in the justice and security domain.

Responsibilities

• Design and develop enterprise applications using Java and Spring Boot
• Implement backend services using Kotlin
• Design and maintain event-driven architectures using Kafka
• Develop REST APIs and integration services
• Apply Domain Driven Design (DDD) principles
• Develop Angular frontend components
• Implement test automation using JUnit and Playwright
• Work with PostgreSQL and Oracle databases
• Support CI/CD pipelines and software quality processes
• Participate in Scrum ceremonies and Agile delivery
• Create and maintain technical documentation in German
• Collaborate with architects, product owners and development teams

Mandatory Skills

Backend

• Java
• Spring Boot
• Spring Framework
• Spring Data
• Spring Security
• REST APIs

Frontend

• Angular (v20+)
• Angular Architecture
• Signals
• TypeScript
• Playwright / frontend testing

Databases

• PostgreSQL
• Oracle
• SQL
• Database modelling

Architecture

• Domain Driven Design (DDD)
• Microservices Architecture
• Event-Driven Architecture

Messaging

• Kafka

Programming Languages

• Kotlin

Testing

• JUnit
• Playwright

Tools

• IntelliJ
• Maven
• Git
• Jenkins
• SonarQube

Methodology

• Scrum
• Agile

Education

• Degree (HF, FH, Bachelor, Master or equivalent) in Computer Science or Business Informatics

Languages

• German C1 mandatory
• English B2-C1 preferred
• French B1+ preferred

Ideal Candidate Profile A Senior Software Engineer with extensive Java and Kotlin experience who has implemented Kafka-based event-driven systems, applied Domain Driven Design in enterprise environments and worked within public-sector or highly regulated environments.

SThree_Germany is acting as an Employment Business in relation to this vacancy.