About this role
Workster is partnering with a fast-growing international technology company within the sports betting and iGaming industry to recruit a Senior Back-End Engineer for their team in Sofia, Bulgaria.
This is an opportunity to work on high-performance, real-time sports betting products, building the systems and services that power complex betting operations. You will take ownership of backend development, architecture, integrations, and performance while working in an engineering environment where scalability, reliability, and speed are essential.
Your RoleDesign, develop, and maintain high-performance backend services and applications
Build scalable systems capable of handling high volumes of real-time transactions and data
Develop and maintain APIs, microservices, and integrations with internal and third-party systems
Contribute to the architecture and continuous evolution of the company’s sports betting platform
Work with real-time sports data, betting feeds, pricing, and other platform integrations
Design reliable solutions capable of supporting significant traffic during major sporting events
Optimise backend services for performance, scalability, availability, and security
Design and maintain database structures and data-processing solutions
Write clean, maintainable, well-tested, and reusable code
Troubleshoot complex production issues and implement long-term technical solutions
Collaborate closely with Front-End, Product, QA, DevOps, and other engineering teams
Participate in code reviews and contribute to engineering standards and best practices
Mentor less experienced engineers and support knowledge sharing across the development team
Contribute to technical planning, estimation, and architectural decision-making
Your Qualifications5+ years of professional back-end software development experience
Strong experience with a modern server-side programming language and its ecosystem
Solid experience designing and developing RESTful APIs and microservices
Strong knowledge of relational and/or NoSQL databases such as PostgreSQL, MongoDB, Redis, or similar
Experience developing high-traffic, high-availability, or real-time applications
Good understanding of distributed systems, asynchronous processing, and event-driven architectures
Experience with messaging technologies such as Kafka, RabbitMQ, or similar is an advantage
Strong understanding of software architecture, design patterns, and clean coding principles
Experience with Git, CI/CD pipelines, automated testing, and modern development workflows
Familiarity with Docker, Kubernetes, AWS, or other cloud technologies is highly advantageous
Good understanding of application security, monitoring, logging, and performance optimisation
Strong analytical and problem-solving skills
Ability to take ownership of complex technical challenges and work independently
Strong English communication skills
Previous experience within sports betting, iGaming, fintech, trading, or another high-transaction technology environment is highly advantageous
The OfferSenior-level position within a growing international sports betting technology company
Opportunity to develop the core systems behind real-time, high-traffic betting products
Modern technology stack and engineering-focused working environment
High level of ownership over backend architecture and technical solutions
Opportunity to influence scalability, performance, and platform development
Collaborative international engineering team
Professional development and career growth opportunities
Exposure to complex real-time data and high-volume transactional systems
Opportunity to work with modern cloud, microservices, and distributed-system technologies
Modern working environment in Sofia, Bulgaria
Long-term opportunity within a fast-growing technology business