Senior Java Developer
Primary stack
Nice to have's
Job description
About the Position
At Optimax Energy, we have been developing smart solutions for automated trading systems and promoting the transition to green energy for over 10 years. This makes us a leader in international electricity trading. We are currently seeking a Senior Java Developer to join our Integrators team in Leipzig, Germany.
Responsibilities
As a Java Developer in our Integrators team, you will play a crucial role in maintaining and enhancing our existing services while driving innovation by:
- Gathering and refining requirements by directly collaborating with stakeholders.
- Developing new features for the trading platform.
- Writing unit and integration tests, maintaining high code coverage.
- Maintaining and troubleshooting services that provide essential market data for trading decisions, ensuring system reliability, scalability, and overall software quality.
- Conducting code reviews and collaborating with peers to maintain high-quality standards.
- Participating in workshops and encouraging knowledge sharing.
- Writing technical documentation.
Requirements
Must-Haves
- Degree in computer science or comparable field of study
- At least 5 years of professional software development experience, including 3+ years in Java (senior level).
- Understanding of Object-Oriented software design patterns and CLEAN code principles.
- Familiarity with threads, Java Executors, concurrency models, and asynchronous programming.
- Experience in implementing efficient data structures and data processing.
- Familiarity with unit and integration testing.
- Good communication skills in English (at least B2).
- Residence in Germany and a valid work permit.
Current Tech Stack
We work with the following tech:
- Java, Spring Boot, MySQL, ClickHouse, Kafka, RabbitMQ.
- Integrations: HTTP, AMQP, WebSockets, R Sockets, STOMP and email; using JSON, CSV, XML, EDI and other formats.
- CI/CD: GitLab, Maven, Jenkins, TestContainers, SonarQube, Portainer and Kubernetes.
- Monitoring: Micrometer, Grafana, Graylog.
Nice to Have
- Experience building and managing Java projects with Maven.
- Experience with Docker, Jenkins, CI/CD pipelines.
- Experience designing and consuming API services.
- Experience with message brokers and asynchronous messaging in general (e.g., RabbitMQ, Apache Kafka).
- Knowledge of Spring Framework (Boot, Web, Messaging, Security).
- Familiarity with agile methodologies (Scrum, Kanban).
- Basic SQL skills for writing queries and understanding relational databases.
- Performance tuning, profiling, and optimization.
- Understanding of common software architecture notations and standards (UML, C4).
- Background in energy markets or trading.
We Offer
Salary: 65,000–75,000€ gross/year - depending on your experience
Health & well-being:
- Freshly cooked lunch every day
- Massages and Pilates in the office
- EGYM Wellpass
- Sports and mobility offers, such as subsidies for a new bike
Flexible working arrangements and benefits:
- 30 days paid vacation
- Flexibility in working hours depending on company needs
- Additional vacation for the honeymoon
- Subsidies for childcare
Team culture and working atmosphere:
- Regular team events (game night, table tennis tournament, excursions, etc.)
- Work in a mission-oriented, international team that values diversity and equality
- Working atmosphere with open doors and flat hierarchies
- Modern, green office in the heart of Leipzig
Professional development and further training:
- Independence and responsibility in project management
- 10% of weekly working time for personal and professional development
About the Company
At Optimax Energy, we have been developing smart solutions for automated trading systems and promoting the transition to green energy for over 10 years. This makes us a leader in international electricity trading. Our culturally diverse team shares a common vision and fosters a culture of appreciation and equal opportunities. We believe that we can achieve extraordinary things if we develop freely. That's why we place great value on a healthy work-life balance and encourage creative freedom.
We embrace diversity, equality, and inclusion. Different perspectives and backgrounds strengthen our team and lead to creative solutions. To achieve this, we create an appreciative working environment that recognizes the uniqueness of all employees and retains talent in the long term.
© Optimax Energy. This job description was sourced from the employer's public career page. TheJob is not the employer — we index the posting and route candidates to the source. All content rights and hiring decisions belong to the employer.
We are active participants on 3 official exchanges and other trading venues in about 8 countries around Europe. Our clients are renewable energy producers, energy suppliers and other trading companies.With offices in Leipzig and Sofia, Optimax is a trading firm that operates around the clock and around Europe, including Germany, France, Denmark, Netherlands, UK, Austria, Slovenia, Bulgaria. More countries are following soon.Our trading is based on our own proprietary models.Quantitative and fundamental analysis and insights into related markets enable us to trade even into most competitive markets. Technology is at the core of how we approach trading, and we consider ourselves as much a technology company as a trading firm.