Senior Java Developer

Twoday; København; On-site; DKK 900,000 - 1,300,000; Full time

Job summary

Twoday is seeking a Senior Java Developer to join a Copenhagen-based project for a major public-sector customer. You will focus on backend development in Java, while coordinating with a Vue.js frontend.

You will design APIs, build event-driven integrations, write tests, and collaborate across teams to deliver high-quality software for a Danish public-sector collaboration platform. Fluency in Danish and English is required, with full-time onsite work in Copenhagen.

Qualifications

• Several years of professional Java development experience.
• Strong hands-on experience with Spring Boot.
• Experience developing APIs and integrations.
• Experience with automated testing and modern development practices.
• Understanding of CI/CD, containerisation and deployment.
• Ability to work independently while contributing actively to the team.
• Strong communication skills and an interest in understanding complex business domains.
• Professional fluency in Danish and English.
• Able to work full time onsite in Copenhagen.

Responsibilities

• Developing new backend functionality in Java and Spring Boot.
• Designing and implementing APIs and event-driven integrations.
• Writing automated unit and integration tests.
• Working with database changes and data models.
• Contributing to code reviews, technical discussions and solution design.
• Troubleshooting and maintaining quality throughout the delivery process.
• Collaborating with developers and stakeholders across organisational boundaries.

Skills

Java development

Spring Boot

APIs & integrations

Automated testing

CI/CD

Containerisation

Team collaboration

Danish & English

Onsite work

Tools

Java

Spring Boot

OpenAPI 3

Kafka

Spock

Liquibase

SQL Server

Azure DevOps

Docker

Kubernetes

Gradle

Vue.js (adv)

Job description

Twoday is the leading digital transformation partner in Northern Europe with a global presence. With approximately 3,000 specialists, we collaborate with some of the most admired private and public organisations to deliver cutting-edge digital solutions. Our expertise spans software engineering, Data & AI, cloud platforms, digital experiences and business applications.

Permanent position at Twoday | Copenhagen

Senior Java Developer

Would you like to develop new digital solutions that support collaboration across the Danish criminal justice system? We are looking for an experienced Java Developer to join Twoday, with your first assignment being for a major public-sector customer in Copenhagen.

Your role

You will join a team developing a new solution that supports digital collaboration across public authorities. Your primary focus will be backend development in Java, although you will work closely with a frontend built in Vue.js.

Your responsibilities will include:

• Developing new backend functionality in Java and Spring Boot
• Designing and implementing APIs and event-driven integrations
• Writing automated unit and integration tests
• Working with database changes and data models
• Contributing to code reviews, technical discussions and solution design
• Troubleshooting and maintaining quality throughout the delivery process
• Collaborating with developers and stakeholders across organisational boundaries

Technology stack

The core backend stack includes:

• Java 25
• Spring Boot 3.5
• OpenAPI 3
• Kafka
• Spock
• Liquibase
• Microsoft SQL Server
• Azure DevOps
• Docker
• Helm
• Gradle

The frontend is built with Vue.js 3.5, TypeScript, pnpm, Quasar, Vite and Cypress. Frontend experience is not required, but experience with Vue.js would be an advantage.

A limited part of the solution integrates with the Danish Police using JAX-WS, Apache CXF 4, SOAP and XML. Experience with these technologies would be beneficial, but is not a requirement.

About You

We expect you to have:

• Several years of professional Java development experience
• Strong hands-on experience with Spring Boot
• Experience developing APIs and integrations
• Experience with automated testing and modern development practices
• An understanding of CI/CD, containerisation and deployment
• The ability to work independently while contributing actively to the team
• Strong communication skills and an interest in understanding complex business domains
• Professional fluency in Danish and English
• Able to work full time onsite in Copenhagen

Experience with Kafka, Spock, Liquibase or public-sector solutions would be an advantage.

Working at Twoday

At Twoday, you will become part of a strong professional environment where collaboration, knowledge sharing and high-quality software development are central. You will work closely with experienced colleagues while helping our customers digitalise complex and socially important processes.

The position is based in Copenhagen and requires full-time onsite presence with the customer.

About Twoday

Twoday operates from modern offices across 30 locations in Norway, Sweden, Denmark, Finland, and Lithuania. We have a strong and unique social environment with highly engaged employees. If you are the candidate we are looking for, you will play a central role with exciting opportunities to grow within an international and innovative group, working on cutting-edge technology and software solutions. You will also have the flexibility to occasionally work from one of our main offices in Oslo, Stockholm, Copenhagen, Helsinki or Vilnius.

Diversity & inclusion

Do you not meet all the requirements? Studies show that women and minorities are less likely to apply for a job if they don't meet every qualification. At Twoday, we are committed to building a workplace and community where everyone is welcome. If you are excited about this role but your previous experience doesn't perfectly align with the job description, we still encourage you to apply.