{"id":3271511,"url":"https://alion.io/job/bullfinch-recruitment-senior-back-end-engineer","title":"Senior Back-End Engineer","company":{"id":4418538,"name":"Bullfinch Recruitment","domain":"bullfinchrecruitment.com","url":"https://alion.io/company/bullfinchrecruitment","size_band":"201-500","is_staffing_agency":true,"employer_type":"agency","is_intermediary":false,"listed_via":null,"ats_vendor":"Breezy","truth_index":{"grade":"A","score":100,"open_postings":4,"ghost_share":0,"stale_share":0,"repost_share":0,"time_to_fill_p50_days":37,"computed_at":"2026-11-05T05:54:30Z"}},"role":"Backend","role_family":"Backend","seniority":"senior","employment_type":"full_time","work_mode":"hybrid","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"explicit","locations":["Sofia, Bulgaria"],"countries":["BG"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":40000,"max_usd":77000,"period":"year","method":"role_seniority_country_cell","sample_n":8},"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Apache Pulsar","optional":false},{"name":"JavaScript","optional":false},{"name":"Nest.JS","optional":false},{"name":"Node JS","optional":false},{"name":"Rest API","optional":false},{"name":"TypeScript","optional":false},{"name":"Aerospike","optional":true}],"status":"live","first_seen_at":"2026-10-26T09:39:32Z","employer_posted_date":"2026-10-26","last_verified_at":"2026-11-05T22:23:51Z","board_verified":true,"closed_at":null,"days_open":10,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":10},"description":"Senior Back-End Engineer\nSofia, Bulgaria | Hybrid | Full-time\nAbout\nGlobal technology company providing B2B SaaS solutions for online sports platforms. The company develops sportsbook software and data-driven technology that enables betting operators to deliver reliable, high-performance sports betting experiences across international markets.\nThe Role\nWe are looking for a Senior Back-End Engineer to join our team in Sofia, contributing to the development and evolution of our sportsbook platform.\nYou'll work within a microservices-based architecture, building and maintaining API-driven services that support complex, high-performance applications. Working closely with other engineers, you'll contribute to new feature development, system optimisation and the continued improvement of our technical infrastructure.\nKey Responsibilities\nDevelop and maintain API-based backend services and applications.\nBuild and enhance services using JavaScript, TypeScript, Node.js and NestJS.\nContribute to the design and implementation of new product features.\nWork with a microservices architecture and technologies including MongoDB and Pulsar.\nOptimise applications for performance, scalability and reliability.\nTroubleshoot and resolve complex technical issues.\nWrite clean, maintainable code and contribute to code reviews and engineering best practices.\nCollaborate with colleagues across an international engineering team.\nWhat We're Looking For\nStrong commercial experience with Node.js development.\nProficiency in JavaScript (ES6+) and/or TypeScript.\nExperience working with NestJS.\nGood understanding of RESTful APIs and backend service design.\nStrong analytical and problem-solving skills.\nExcellent communication and teamwork abilities.\nGood written and spoken English.\nDesirable Experience\nExperience operating mature API products in production.\nExposure to high-load systems and scalable architectures.\nExperience with Apache Pulsar, Aerospike or similar technologies.\nA degree in Computer Science, Software Engineering, Mathematics or a related discipline.\nPackage:\nAn international and multicultural working environment.\nHybrid working in Sofia.\nFlexible working hours.\nUp to 24 days of paid annual leave.\nFood vouchers and additional health insurance.\nSports card and office perks.\nCareer development opportunities and team-building activities.\nLocation: Sofia, Bulgaria | Working arrangement: Hybrid | Employment type: Full-time","description_format":"text","description_chars":2440,"description_truncated":false,"requirements":{"experience_years_min":null,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":{"level":"bachelor","optional":false},"security_clearance":false,"languages":[{"language":"English","level":"All levels","optional":false}]},"benefits":["Annual leave","Flexible schedule","Health insurance","Hybrid work"],"hiring_locations":[{"name":"Bulgaria","iso":"BG","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":[],"lifecycle":[{"event":"open","at":"2026-10-26T11:57:23Z"}],"visa":[],"liveness":{"score":54,"band":"ok","label":"Likely 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