Spalah is a Ukrainian venture builder that connects ambitious tech businesses with the international stage fostering an ecosystem for rapid growth. We unite visionary founders and diverse talent to create companies that drive global progress.Our portfolio features over 10 projects spanning Adtech Martech Mobile apps and more. We’re looking for a Backend Developer to build and develop AdTech publishment services — systems responsible for ad serving traffic delivery and monetization logic. Experience with OpenRTB or integrations with ad networks is a strong plus. You’ll join our core backend team led by the CTO — a group of experienced engineers building the infrastructure behind ad delivery and monetization. The team works within a stable business model and has strong expertise in developing scalable data-driven AdTech platforms. What you will be doing build and maintain scalable Node.js services (ES6+) improve application performance through profiling optimization and best practices enhance refactor and modernize existing codebases design efficient data models and work with SQL/NoSQL databases including query optimization and caching write and maintain unit and integration tests and contribute to high-quality code through code reviews troubleshoot and resolve production issues in Linux environments ensuring system stability and reliability. What you bring hands-on experience with RTB / DSP / SSP / ad serving pipelines 3–5+ years of backend development experience with Node.js Go or Python strong understanding of asynchronous and concurrent programming experience building high-throughput / low-latency systems strong SQL skills (MySQL/PostgreSQL) indexing query optimization execution plans transactions hands-on experience with Redis/MongoDB and caching strategies confident debugging and profiling skills solid understanding of HTTP/TCP and distributed systems strong command of Linux CLI and Git clean code approach with focus on performance scalability and reliability. Bonus skills AdTech / OpenRTB 2.x/3.x (auctions bid req/resp schain ads.txt/sellers.json) ClickHouse Aerospike Nginx parallel/stream data processing experience with high-load/distributed systems Kafka or RabbitMQ. What we offer you flexibility and freedom choose fully remote hybrid or office-based work yourself strong team work alongside some of the industry’s top talent unlimited growth grow in multiple directions get freedom to launch your own product career development take courses attend top-notch conferences explore digital library for nonstop growth health support get medical insurance paid vacation and sick leaves and access to a corporate psychologist fun and culture enjoy off site parties team-buildings sport events and corporate gifts. Thanks for your time.Let`s bring things to the next level?