Full Stack Developer – Modern Backend & Frontend

Twoday Denmark; København; On-site; DKK 650,000 - 900,000; Full time

Job summary

Twoday is seeking an experienced Full Stack Developer to work on business-critical digital solutions within the Danish healthcare sector. You will contribute to the development, modernisation and maintenance of complex healthcare systems, collaborating with developers, architects, testers and DevOps across multiple suppliers.

The role covers backend services, REST APIs, and modern frontend apps, with emphasis on secure API communication and data-driven design.

Qualifications

• Solid professional fullstack development experience.
• Strong backend experience with C#/.NET, Java/Spring Boot or comparable technologies.
• Experience with JavaScript/TypeScript and modern frontend frameworks (React/Angular/Vue).
• Experience with REST APIs, integrations and relational databases.
• Understanding of OAuth2/OpenID Connect, secure coding and API security.
• Knowledge of event-driven architecture, idempotency and asynchronous processing.
• Experience with automated testing, Git and CI/CD.
• Experience in complex enterprise environments.
• Fluent Danish, written and spoken.

Responsibilities

• Developing and maintaining backend services, REST APIs and modern frontend applications.
• Building secure, reliable integrations between systems.
• Working with relational databases and data-driven applications.
• Implementing authentication, authorisation and secure API communication.
• Contributing to event-driven solutions and asynchronous processing.
• Developing automated tests and supporting CI/CD and deployments.
• Troubleshooting production issues and improving system performance and stability.
• Collaborating across teams and suppliers on technical design, documentation and delivery.

Skills

Fullstack dev

Backend with C#/.NET

Java/Spring Boot

Frontend with JS/TS

REST APIs

OAuth2/OpenID Connect

Event-driven architecture

Automated testing & CI/CD

Git

Danish language

Tools

Docker

Kubernetes

Infrastructure as Code

Job description

Permanent position at Twoday | Copenhagen

Full Stack Developer – Modern Backend & Frontend

Twoday is looking for experienced Full Stack Developers to work on business-critical digital solutions within the Danish healthcare sector.

You will join our Digital Engineering organisation and contribute to the development, modernisation and maintenance of complex healthcare systems, working closely with developers, architects, testers and DevOps specialists across multiple suppliers.

Your role

You will work across the full technology stack, from backend services and integrations to frontend applications, testing and production support.

Your responsibilities will include:

• Developing and maintaining backend services, REST APIs and modern frontend applications

• Building secure, reliable integrations between systems

• Working with relational databases and data-driven applications

• Implementing authentication, authorisation and secure API communication

• Contributing to event-driven solutions and asynchronous processing

• Developing automated tests and supporting CI/CD and deployments

• Troubleshooting production issues and improving system performance and stability

• Collaborating across teams and suppliers on technical design, documentation and delivery

What we're looking for

• Solid professional fullstack development experience

• Strong backend experience with C#/.NET, Java/Spring Boot or comparable technologies

• Experience with JavaScript/TypeScript and modern frontend frameworks such as React, Angular or Vue

• Experience with REST APIs, integrations and relational databases

• Understanding of OAuth2/OpenID Connect, secure coding and API security

• Knowledge of event-driven architecture, idempotency and asynchronous processing

• Experience with automated testing, Git and CI/CD

• Experience working in complex enterprise environments

• Fluent Danish, both written and spoken

Experience with Docker, Kubernetes, Infrastructure as Code and multi-supplier delivery environments is an advantage.

The employment

You will be permanently employed by Twoday, with your first assignment supporting critical public-sector healthcare systems in Copenhagen.

The assignment requires full-time onsite presence at the customer location.

You will work in a collaborative technical environment where quality, security, knowledge sharing and responsibility for reliable software delivery are essential.

We look forward to hearing from you.

Working at Twoday

Twoday is a leading technology consulting company specializing in applied AI and advanced engineering. With around 2,300 experts in AI, data, digital engineering, and cloud engineering, we cut through complexity, remove uncertainty, and prove the value of technology.

Our purpose is to create a better tomorrow through AI and technology. We strengthen private and public organizations across energy and utilities, financial services and insurance, industrials and manufacturing, health and life sciences, and government.

However, our greatest strength isn't the technology we work with. It's the people behind it. Every day, they bring together expertise, curiosity, and determination to help our customers solve complex challenges and create lasting value.

Diversity and inclusion

We are committed to building an inclusive and diverse workplace where everyone is treated with respect and has equal opportunities. Our recruitment decisions are based on competencies, experience, and individual merit.