Subsets (YC S23) is an early-stage startup building the future of AI-driven subscription growth. As a Senior Software Engineer, you’ll join the early team building the future of subscription lifecycle management, helping brands create audiences, run experiments, and optimize how messaging impacts churn, retention, upsell and more! What you will do - own and ship new features from idea to production - build product and platform capabilities for audience creation, experimentation, and lifecycle insights - work closely with the founders and team to shape product direction and technical decisions - improve the performance, reliability, and scalability of systems that power customer messaging workflows - use customer problems and data to inform what we build next Tech Stack: - backend: .NET 10, Entity Framework Core, PostgreSQL, Redis - frontend: React.js, Vite, Tailwind CSS, shadcn/ui. - infrastructure & CI/CD: Google Cloud Platform (GCP), Terraform, GitHub Actions. It's not required to have prior experience with our chosen technologies. You may be a good fit if - you have a strong bias toward action and the ability to work autonomously in fast-paced, loosely defined environments. - you have experience with Claude Code or similar - you have an "anti-meeting" culture mindset and value focused work time. - you prefer a primarily in-office way of working - you’re energized by the pace and intensity of early-stage startups Perks - competitive salary & equity - company card for all things office food/snacks - great breakfast and lunch (and dinner when working late in the office) - relocation support if you don't live in Copenhagen - office kayaks 🛶