Senior Fullstack Engineer (TikTok)

We’re looking for a Senior Fullstack Engineer to help build and evolve Smartly’s TikTok offering, enabling some of the world’s largest advertisers to create, manage, automate, and optimize their TikTok campaigns at scale. TikTok is an important part of Smartly’s multi-channel advertising offering. The capabilities you build will directly shape how our customers run their advertising on the platform — from the experiences they use to create and manage campaigns to the automation, services, and integrations behind them. If you enjoy solving complex product and engineering problems, meaningful ownership, and seeing your work have a direct impact on customers, this is a role where you’ll get all three. You’ll work end-to-end across the stack — from building intuitive user experiences to designing the services and integrations behind them. You’ll also have the opportunity to explore how AI and automation can help us build better products and improve how we work as engineers. You’ll have real influence over both what we build and how we build it. You’ll take significant product capabilities from idea to production, contribute to architectural and product decisions, and make pragmatic trade-offs between user experience, scalability, reliability, and speed. You’ll work closely with experienced engineers, product managers, and designers who enjoy solving difficult problems together and learning from each other. As a senior engineer, you’ll also mentor others, share knowledge, and help us continuously improve how we build software. Our tech stack Backend: Node.js, TypeScript Frontend: React, TypeScript Infrastructure: PostgreSQL, Redis, Kubernetes Architecture: Distributed systems, event-driven services, large-scale data processing What you’ll do Own significant TikTok product capabilities end-to-end, from customer-facing experiences to the services and APIs behind them Build intuitive, high-quality user experiences for creating, managing, and automating advertising campaigns Design and operate distributed, data-intensive systems and services at scale Build and evolve APIs and integrations that connect Smartly with TikTok and the rest of our platform Drive technical and architectural decisions across the stack and contribute to long-term technical direction Partner closely with product and design to understand customer problems and shape solutions, not just implement them Collaborate across engineering teams to create a consistent experience across Smartly’s advertising platform Mentor other engineers and help raise the bar for engineering quality and practices What we’re looking for Strong experience building and operating production-grade applications across the stack, ideally with TypeScript, Node.js, and React or similar technologies Experience taking product capabilities end-to-end, from customer-facing experiences to backend services and APIs Experience designing distributed systems and working with asynchronous, event-driven architectures at scale Ability to build reliable systems and integrations that handle high volumes of data Ability to take ownership of complex problems and drive them from concept to production Strong collaboration skills and experience working closely with engineering, product, and design to shape solutions A pragmatic approach to engineering, balancing user experience, technical quality, customer needs, and speed Interest in mentoring other engineers and contributing to strong engineering practices Ability and willingness to work in a hybrid setup from our Helsinki office, 3 days per week What We Offer You At Smartly, we offer a place where you can advance your career. Here, you'll find: An Inclusive Global Culture: Join a team of over 750 Smartlies, representing more than 60 nationalities across 24 locations in 13 countries. We cultivate a culture built on trust, transparency, and open feedback, where diverse perspecti