Senior Engineer (Node.js) – AdTech / RTB

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 will join a small, senior engineering team with direct influence on architecture, performance, and technical direction.

• 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

Nice to have:

• 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 systems

• 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 optimization