Senior Java Developer

About the role

Roller Gaming is seeking a Senior Java Developer to join its growing engineering teams based in Sofia and London as a key contributor to high-performance, transaction-driven systems within the iGaming and iLottery sectors. The successful candidate will own the design and delivery of modular, scalable, and portable solutions that underpin critical revenue-generating services for global lottery industry leaders. You will actively participate in the full stack development lifecycle, from design and implementation through rigorous code review, ensuring that every solution meets strict standards of quality and reliability. This role emphasizes a service-oriented or microservices architecture where your work will directly influence player engagement platforms, interactive games, and operational efficiency. You will craft clean, reusable code while collaborating closely with cross-functional teams in an environment that values transparency, loyalty, and mutual respect. If you thrive in a fast-paced, innovative space and are passionate about shaping the future of gaming technology, this is your opportunity to make a significant impact.

Key facts

What you'll do

Design and develop new features and functionality for high transaction, large scale websites and services using Java, ensuring robust performance under demanding conditions.

Participate actively in the design, implementation, and code review process of full stack end-to-end solutions to maintain architectural integrity and code quality.

Architect and deliver modular, scalable, and portable solutions that align with project requirements and long-term product vision.

Write clean, readable, and reusable code within specified deadlines while adhering strictly to agile methodology and best practices.

Organize and prioritize work effectively in collaboration with product owners and stakeholders to guarantee timely project delivery and milestone achievement.

Create and maintain comprehensive testable code, including unit tests and integration tests, to support long-term maintainability and system stability.

Work with relational databases such as PostgreSQL to optimize data models, queries, and transactions for maximum efficiency and reliability.

Leverage message queues such as RabbitMQ, Kafka, or similar technologies to build resilient, event-driven communication layers across services.

Utilize Docker and Kubernetes to containerize applications and manage deployment pipelines, with AWS experience providing an additional layer of operational insight.

Contribute to the evolution of CI/CD pipelines using tools such as Jenkins, Bamboo, and GitLab to automate testing and streamline releases.

Apply reactive programming principles using frameworks like Vert.x to build non-blocking, high-throughput components that enhance system responsiveness.

Maintain strong version control practices across repositories in Bitbucket and GIT, ensuring traceability and consistency across all development activities.

Demonstrate practical knowledge of container orchestration, specifically Docker and Kubernetes, to support resilient and scalable deployments.

Exhibit excellent problem-solving skills and the ability to work both independently and within a collaborative team setting.

Requirements

Demonstrate a proven track record of successfully completed projects with extensive experience in Enterprise Java Software Development within service-oriented or microservice architectures.

Showcase proficiency in Java with a minimum of 6 years of hands-on experience in back-end programming, along with deep expertise in related frameworks such as Spring, Spring Boot, and Hibernate.

Provide evidence of designing, building, and maintaining robust RESTful APIs that are scalable and easy to integrate across multiple systems.

Display experience working with relational databases, particularly PostgreSQL, including performance tuning, schema design, and complex query optimization.

Bring hands-on experience with message queues such as RabbitMQ, Kafka, or similar platforms to implement reliable asynchronous processing and data streaming.

Highlight experience with Docker, Kubernetes, and AWS, where familiarity with cloud infrastructure and container orchestration significantly enhances operational capabilities.

Illustrate competence with CI/CD pipelines, having practical exposure to tools like Jenkins, Bamboo, and GitLab to automate builds, tests, and deployments.

Show preference for reactive programming using Vert.x or similar frameworks, focusing on non-blocking patterns that improve scalability and resource utilization.

Demonstrate mastery of Version Control Systems, specifically Bitbucket and GIT, with a strong understanding of branching strategies, pull requests, and code governance.

Apply practical knowledge of containers, primarily Docker, ideally coupled with Kubernetes expertise for managing containerized applications in production environments.

Exhibit strong analytical and troubleshooting skills, with the ability to diagnose issues quickly and implement effective solutions under pressure.

Possess excellent communication skills in both English and Bulgarian, enabling clear conveyance of technical concepts to both technical and non-technical stakeholders.

Hold a Bachelor's degree in Computer Science, Software Engineering, or a related technical field, or equivalent professional experience that demonstrates deep technical competence.

Commit to working in a hybrid or remote setup based from Bulgaria, with flexibility to collaborate across multiple time zones as needed.

Nice to have

Experience with reactive programming using Vert.x or similar frameworks is preferred.

Familiarity with AWS services and cloud-native architectures provides additional advantage.

Background in the iGaming or lottery industry is considered a beneficial context for understanding domain-specific challenges.

Practical notes

This position supports hybrid or fully remote work arrangements originating from cities across Bulgaria.

Successful candidates should be prepared to engage in ongoing professional development, including company-sponsored training and collaborative internal events.

The role involves participation in company social activities, charity initiatives, and sports events as part of team building and culture reinforcement.