At NFON AG, we revolutionise communication across Europe as a leading pan-European provider of cloud-based telephone systems. Operating in 18 countries, we proudly serve over 55,000 customers with more than 500,000 customer extensions and a robust network of 3,000+ partners. Since our foundation in 2007, NFON AG has experienced rapid growth, fueled by our unwavering energy and drive. We believe in the limitless potential of our ideas and the transformative impact they can have - not just for our customers, but for our employees as well. Simplifying complexity is our specialty. We understand the challenges, but we also know that communication should be effortless, intuitive, and seamless. That's why we're at the forefront of delivering cutting-edge communication solutions for the workplace of tomorrow. Join us at NFON, where innovation meets simplicity, and together, we’ll shape the future of communication. Imprint: https://www.nfon.com/de/rechtliches/impressum/ Privacy note: https://www.nfon.com/de/privacy-center/datenschutzhinweis-social-media

Your new role

Are you a seasoned Java developer who thrives in technically demanding environments and enjoys the challenge of modernizing legacy systems? At NFON, we’re shaping the future of cloud telephony across Europe, and we're looking for an experienced Java engineer who can help us modernize, optimize, and scale our platform.

As a Senior Java Developer, you’ll play a vital role in evolving our backend systems, from Java 7/8 to more modern stacks, while building robust solutions using industry-standard frameworks and tools.

The work you‘ll do

Modernize and migrate legacy Java systems, specifically transitioning from JDK 7 to JDK 8 and beyond.
Take ownership of backend development using modern Java, with a focus on robust, maintainable, and scalable code.
Drive improvements in our tech stack, including the replacement of OpenJPA with Hibernate.
Collaborate closely with cross-functional teams in architecture, DevOps, and product to deliver secure and scalable RESTful APIs.
Work in complex SQL environments (MariaDB) and contribute to data-heavy business logic.
Support containerization efforts using Docker, and help define future infrastructure evolution (e.g., Kubernetes).
Integrate and support OpenID Connect-based authentication and authorization mechanisms.
Contribute to and improve our CI/CD pipeline, leveraging Git-based workflows.

The qualifications you need

Strong communication skills in English, with the ability to explain complex ideas clearly.
A collaborative mindset, you enjoy working closely with teammates and building strong relationships across functions.
Extensive Java expertise, especially in JDK 7 and JDK 8, including hands-on experience with migration projects.
Deep familiarity with core backend frameworks and build tools, especially: Spring Framework, Hibernate, Maven, Experience with other Java ecosystem tools is a plus.
Strong SQL skills, particularly in MariaDB or similar relational databases.
Experience working in modern development environments: Git, CI/CD pipelines, and automation tooling.
A proactive mindset when it comes to modernizing systems, automating tasks, and reducing technical debt.
Practical understanding of REST API design, and how to build secure and scalable service endpoints.

NICE TO HAVE

Exposure to container orchestration tools like Kubernetes.
Familiarity with infrastructure-as-code practices.
Experience in telecom, VoIP, or platform engineering environments.

What we can offer you

Enjoy a fair and appropriate salary.
Comprehensive health insurance coverage for you and your family.
Benefit from 22 vacation days, exceeding the legal-required standard.
The option to work from home up to 2 days per week.
Work remotely from anywhere up to 20 days per year.
Work in a cosy, modern office equipped with top hardware.
Choose your device – Mac or Windows.
We cover costs for e-learning courses to support your professional development.
Enjoy organic fruit baskets, a smoothie bar, quality coffee, mate, and more.
We are "Certified Family Friendly" and support a healthy balance between work, family, and private life.
Be part of an agile organization where your ideas matter and you have the opportunity to take charge.

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About us

NFON who? 

We’re NFON – a leading European provider of integrated business communication with a focus on AI-based applications and as a licenced telecoms company active in 15 European countries. Since 2019 we are listed in the Prime Standard segment of the Frankfurt Stock Exchange, have nine branch operations and are working together with over 3,000 partners. Every day, we support around 55,000 business customers in Europe with intuitive communication solutions that make their businesses more efficient and flexible.

 What we do… 

As a long-term partner for small and medium-sized businesses, we combine technological innovation with user-friendly and efficient business communication solutions. With both AI-based technologies and operational excellence, we are enabling companies to harness the full potential that artificial intelligence offers – for optimised processes, more precise customer interactions and new growth opportunities. With its core product, the smart cloud communications platform, we are offering hassle-free voice calls, simple video conferencing and seamless integration of CRM and collaboration tools for small and medium-sized companies. All of NFON’s cloud services are operated in certified data centres in Germany, with 100% of their energy needs covered by renewable sources.

How & why we do it    

Our vision is to rethink business communication, inspire and connect people to grow together sustainably. For that we need innovative ideas and people who get things done & never get discouraged. If plan A doesn’t work, the alphabet still has 25 other letters to choose from. There is one thing that builds the foundation of everything we do – and that’s respect. Whether it is towards our employees, our partners or our customers. We value each other’s commitment and listen to diverse opinions. Of course everyone has personal goals. But at the end of the day what counts is the success of the overall team. We work as a team and learn from the people around us.
  

Diversity is at our core.

NFON is an equal opportunity employer and does not discriminate on the basis of ethnicity, religion, color, national origin, gender, sexual orientation, gender identity, age, marital status, veteran or disability status.

Senior Java Developer (wmd)

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