Senior Full-Stack JavaScript Developer – Sports Betting – Sofia, Bulgaria

Senior Full-Stack JavaScript Developer – Sports Betting in Sofia, Bulgaria. Competitive – discussed at interview. At a glance Location: Sofia, Bulgaria Languages: English Salary: Competitive – discussed at interview Start: ASAP Relocation: not offered for this role About the role CloserHire is partnering with a fast-growing international technology company within the sports betting and iGaming industry to recruit a Senior Full-Stack JavaScript Developer for their team in Sofia, Bulgaria. This is an opportunity to work on high-performance, real-time betting products used in a fast-paced environment where scalability, reliability, and user experience are critical. You will take ownership across the full development lifecycle, working with modern JavaScript technologies to build and What you'll do Design, develop, and maintain scalable full-stack JavaScript applications Build responsive and high-performance user interfaces using modern frontend technologies Develop robust backend services, APIs, and integrations supporting real-time sports betting products Work with high-volume, real-time data and ensure applications remain reliable during peak sporting events Design and integrate RESTful APIs, WebSockets, and third-party services Contribute to architectural decisions and help define technical standards and best practices Write clean, maintainable, well-tested, and reusable code Identify performance bottlenecks and optimise applications for speed, scalability, and reliability Collaborate closely with Product, UX/UI, QA, DevOps, and other engineering teams Participate in code reviews and support the continuous improvement of development processes What we're looking for 5+ years of professional software development experience, with strong expertise in JavaScript/TypeScript Strong experience with modern frontend frameworks such as React, Next.js, or similar Strong backend development experience with Node.js Solid understanding of TypeScript, HTML5, CSS3, and modern JavaScript Experience designing and consuming REST APIs and working with real-time technologies such as WebSockets Experience with relational and/or NoSQL databases such as PostgreSQL, MongoDB, or Redis Good understanding of software architecture, design patterns, and scalable application development Experience with Git, CI/CD pipelines, automated testing, and modern development workflows Familiarity with cloud environments and containerisation technologies such as AWS, Docker, and Kubernetes is an advantage Strong understanding of application performance, security, and reliability Excellent analytical and problem-solving skills Salary Competitive – discussed at interview Bulgaria applies a flat 10% income tax, and living costs in Sofia, Plovdiv and Varna run well below Western European levels — the take-home goes considerably further than the headline suggests. Benefits Senior-level position within a growing international sports betting technology company Opportunity to work on complex, real-time and high-traffic products Modern technology stack and engineering-focused environment High level of ownership and influence over technical decisions Opportunity to contribute to architecture, scalability, and product development Collaborative international engineering team Professional development and career growth opportunities Exposure to the latest technologies within the sports betting and iGaming industry Modern working environment in Sofia, Bulgaria Long-term opportunity within a fast-growing technology business Why Bulgaria? Bulgaria is one of the best-value moves in Europe right now — city living at a fraction of Western European costs, an established international community, and a flat 10% income tax. How the process works Apply with your CV — we read every application A short introductory call with CloserHire, around 30 minutes Interview with the company Offer, then we help with the paperwork and, where relevant, the move From application to starting on the ground usually takes around five weeks. CloserHire recruits for this role on behalf of our client. We are an equal-opportunity recruiter and consider every applicant on ability alone.