Lead Engineer (Node.js) – AdTech / RTB

You’ll work on backend systems where milliseconds directly impact business results.Our client is a Finnish AdTech company building a programmatic advertising platform that processes real-time auctions and makes ad-serving decisions in milliseconds.You’ll join a small, senior engineering team with direct influence on architecture, performance and technical direction.Requirements description・Strong commercial experience with Node.js and TypeScript・Experience building high-throughput, low-latency backend systems・Good understanding of distributed systems, scalability and performance optimization・Experience designing and maintaining production-grade APIs and backend services・Ability to make independent technical decisions and take ownership of solutions・Fluent English・Experience with RTB / programmatic advertising・Knowledge of OpenRTB 2.5 / 2.6・Experience with IAB standards and ad formats・Background in DSP, SSP, ad exchanges or Prebid・Experience with event-driven architectures, caching and performance-sensitive systemsYour responsibilities・Build and scale high-throughput, low-latency backend services using Node.js and TypeScript・Work on real-time bidding flows, integrations and performance-critical backend components・Design solutions for systems processing large volumes of concurrent requests・Optimize latency, throughput, reliability and resource usage・Take ownership of technical and architectural decisions・Work closely with experienced engineers on production systems where performance matters・Investigate bottlenecks, production issues and opportunities for further optimizationWhat you get・100% remote- private medical healthcare and multisport.・Work in a small, senior engineering team・Real influence on architecture and technical decisions・Access to modern AI engineering tools with high usage limits・A practical AI culture where tools support engineering work, while technical judgment remains with the engineer・Work on a product where backend performance, scalability and latency have a direct and measurable impact