
You have experience, a broad view, and deep knowledge – and you have great ambition?
You’ve just found your door.
We are looking for a hands-on Lead Java Developer who is ready to take over one of our teams. As the Lead, you will shape the team and take it to the next level. You will be deeply involved in defining how things will run.
Transforming and creating a containerized microservice architecture in Java (or other languages)
Developing new products while combining legacy and monolithic Z1 software with new containerized versions
Renovating, rebuilding — and making it shine
Integrating legacy software components (monoliths) into new product solutions
Proactively planning and developing Z1 products with your team
Finding new paths and solutions to strengthen our market position
Aligning your work with other R&D teams to ensure a smooth fit in the overall architecture
Being part of a cross-functional team that isn’t afraid to explore new technologies or thought patterns
Helping develop the team to the next level
Coordinating your team effectively and understanding its capabilities deeply
Mentoring and guiding team members to deliver the features and results our enterprise customers expect
Analyzing blockers or issues in the development strategy — and preventing them before they happen
You have a modernization mindset: turning complex legacy systems into clean, maintainable architecture
You have successfully worked and led in a development team for at least 7 years, delivering solutions and products together
You have at least 5 years of practical experience working with Java. We primarily use Java 21
You have deep knowledge and understanding of software architectures such as monoliths and microservices
You have experience with security topics such as PKI, S/MIME, OpenPGP, X.509 certificates, and PGP keys
Java: Java 21
Linux: Basic proficiency in Linux commands
Shell Scripting: ANSI Shell, Bash
Frameworks: Spring MVC, Spring Boot, Spring Data, Spring Integration
Message Brokers: NATS / RabbitMQ / Kafka
Containerization: Docker, Kubernetes
Microservice Design: Experience with microservice architectures
Monoliths: Experience working with monolithic applications
Build Tools: Gradle
Software Testing Methodologies
Knowledge of Smart Cards or Hardware Security Modules is not required but is a great advantage.

Zertificon is a leading software manufacturer in the field of IT security since 2004. Our Z1 solutions provide secure electronic business communications, NIS2 & GDPR compliance | For business, healthcare, finance, automotive, government ... Z1 solutions specifically for the energy industry have been around since 2007.
We are a cash-flow funded, independent, founder-managed company. - 120 employees including development and support work for us in Berlin.
Our Z1 solutions offer you maximum automation, intuitive usability, and easy integration!
Our special expertise is in PKI certificate management: automation for S/MIME, OpenPGP & AS4 keys and certificates --> procurement, search, exchange, validation and distribution. We do not only take care of your individual keys and certificates, but - IMPORTANT! - also of the search and management of the certificates of your communication partners. This is the only way to ensure trouble-free, secure communication without having to deal with huge numbers of service desk tickets at the sender's and recipient's end!
Over 25% of the top 100 German companies with the highest turnover already use our Z1 solutions. In the German energy market communications, hundreds of companies send and receive over a million messages a day securely and trouble-free via Z1 solutions.
Visit us at www.zertificon.com