Fullstack Engineer

We’re looking for a Senior Fullstack Engineer to join Smartly and help shape the future of our multi-channel advertising platform. You’ll be working on expanding Smartly into both new and existing advertising channels. Depending on the team, this can mean greenfield development of new integrations or evolving and scaling established ones like Pinterest. While we can’t share all the details yet, this is a highly strategic area for the company with strong leadership visibility and direct revenue impact. Whether you’re building something new or improving existing integrations, the work goes beyond incremental changes. You’ll be building new capabilities, improving existing ones, and helping shape how different channels are integrated into our platform at scale. In this role, you’ll design systems that power automation for some of the world’s largest advertisers. You’ll work closely with partners like Google, Reddit and Spotify, building deeply integrated solutions that enable customers to launch, optimize, and iterate campaigns efficiently. You’ll also have the opportunity to explore how AI and automation shape the future of ad tech, and turn those ideas into production-grade systems. This role is about ownership and technical influence. You’ll contribute to architectural direction, make trade-offs that balance scalability and product needs, and collaborate across teams to create a unified platform experience across channels. Our tech stack Backend: Node.js, TypeScript Frontend: React, TypeScript Infrastructure: PostgreSQL, RabbitMQ, Redis, Kubernetes Architecture: Distributed systems, event-driven services, large-scale data processing What you’ll do Own the design and implementation of new platform integrations end-to-end Design and operate distributed, data-intensive systems and microservices at scale Build automation systems that process large volumes of campaign and performance data Develop and evolve client-facing APIs and backend services Drive architectural decisions and contribute to long-term technical direction Work across teams to align on shared patterns and unify channel behavior within the platform Partner closely with product and design to shape solutions, not just implement them Mentor other engineers and raise the bar for engineering quality and practices What we’re looking for Strong experience building and operating production-grade systems with Node.js and TypeScript Solid frontend experience with React and modern web development practices Experience designing distributed systems and working with asynchronous, event-driven architectures Proven ability to build scalable systems that handle high data volumes Ability to take ownership of complex problems and drive them from concept to production Strong collaboration skills and experience working across teams and disciplines Interest in mentoring and contributing to team-level engineering practices Ability and willingness to work in a hybrid setup from our Helsinki office (3 days per week)