Senior Full-Stack JavaScript Developer – Sports – Sofia, Bulgaria (Growing Team)

A working week in Sofia, Bulgaria, in English. Competitive – discussed at interview. A typical day You'll spend most of it on 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, and contribute to architectural decisions and help define technical standards and best practices. Less often, you'll also 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, and participate in code reviews and support the continuous improvement of development processes. Would you fit? We're looking for someone with 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, and good understanding of software architecture, design patterns, and scalable application development Experience with Git, CI/CD pipelines, automated testing, and modern development workflows. The money 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 Who you'd work for 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 About Bulgaria A flat 10% income tax and some of the lowest living costs in the EU — your salary stretches a long way. Applying Send us your CV and we will come back to you either way A relaxed 30-minute conversation to check the role genuinely fits The company's own interview stage Offer and contract — we stay involved through paperwork and arrival CloserHire recruits for this role on behalf of our client. We are an equal-opportunity recruiter and consider every applicant on ability alone.