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Lead Java Developer IT-Security (f/m/d) at an established IT-Security Company

Berlin
Full-time
Permanent employee

Untertitel

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.

Your tasks

Development and Product

  • 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

Alignment with Other Teams

  • 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

Team Building and Leadership

  • 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

Miscellaneous / Strategic Thinking

  • Analyzing blockers or issues in the development strategy — and preventing them before they happen

Your profile

  • 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

  • Ideally, you already have knowledge of Email, SMTP, JavaMail, and BouncyCastle
  • You demonstrate professional proficiency in both English and German (C1 level or higher).

You are proficient with the following technologies:

  • 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.

We offer

  • Flexible hours and home office options
  • Mobility: free Germany-wide public transport ticket, bike leasing, or parking
  • Subsidies for meals (e.g., delivery services) and home office internet
  • Urban Sports Club membership for flexible fitness and wellness
  • Office perks: rooftop terraces & green courtyard, organic fruit and drinks, personal packages accepted at the office
  • Get-togethers: monthly Pizza Friday, regular team events, big summer party
  • Responsible leadership: structured onboarding, regular feedback, clear goals
  • Innovative without startup risk: profitable for 20+ years, self-funded innovation with strong global potential
  • International team: 120+ colleagues from 30+ countries, open and collaborative culture

About us

Why Zertificon?

Zertificon stands for securing digital business. We develop trusted IT security solutions "Made in Germany" – built for businesses that value both protection and usability.

  • Independent & committed: For over 20 years, we’ve built secure communication tools – as an owner-managed company with a clear stance
  • Purpose-driven: We believe that digital communication must be secure and free. If you think Edward Snowden did the right thing as a whistleblower, we might just share the same values. As a sign of our support, we donate €1,000 to an organization that supports Edward Snowden for every new hire who mentions him in their application
  • Hands-on excellence: We take on complex challenges because we can. Our in-house experts are top-tier – even external specialists often learn from us. When we want the best, we build it ourselves
  • Agile by conviction: We think fast, act pragmatically, and improve continuously. No bloated processes, no “that’s just how it’s always been done.” Initiative is welcome – but of course, it will be challenged, and not every idea will make it through unchallenged
  • Security that works: We build software that’s not only secure, but actually usable – not just for large enterprises with dedicated highly skilled IT teams, but also for small and mid-sized businesses that need strong security without the complexity
  • Diverse & international: Our team of 130 people from 30+ countries shares one mission: making secure digital communication easily accessible to businesses of all sizes

If that resonates with you, we’d love to hear from you.