Founding full-stack developer

Founding Full-Stack Engineer Copenhagen-based (or Sofia) · Full-time · Works directly with the CEO on a new product We're Weply, a profitable SaaS company running hybrid human-AI lead generation focused chat across the Nordics and the Netherlands, with thousands of clients and proprietary conversational models trained on millions of real sales conversations. Now we're building something new on top of that foundation. We're not saying much publicly yet, but it's ambitious, it's AI-native, and it has the potential to become a global business. We're looking for a very talented founding engineer with a product mindset to lead it with us. What you'll do Lead a new product from zero to production, working full-time in a small SWAT team alongside an AI Engineer, with support from the wider engineering, AI and product team when you need it. You'll own the architecture, build across the full stack, and make the foundational calls that everything else is built on. You'll work directly with the CEO, influence strategy, and see real customers use what you ship - fast. Expect hard problems: real-time systems, autonomous AI agents, and outcome-based billing, among others. This is a build-from-scratch role with real ownership, warrants in Weply, and impact from day one. You'll thrive here if you Have 3+ years of professional experience and have taken systems from zero to production, owning the full lifecycle, not just contributed to someone else's architecture.Are excellent across the stack: TypeScript, React, Node.js, PostgreSQL, and real-time/streaming applications.Use coding agents (Claude Code, Cursor, Codex) daily, and pair that speed with the judgment to catch when they're confidently wrong.Have an entrepreneurial instinct: you want to build a company's product foundation, not close tickets. You make good calls with incomplete information and move fast.Bonus: experience integrating LLM APIs, building AI agents, usage-based billing, or embeddable widgets. Experience with NoSQL, document-oriented DB like MongoDB. What we offer Direct line to the CEO and CTO and genuine influence over what we build. The blank canvas of a startup with the stability of a profitable company behind it. You're building something new without betting on runway. For v.1.0 you will work day by day with our CEO, design partners, AI engineer, product and others. Competitive salary, warrants in Weply, hybrid working, 25 days paid leave, and a team across Copenhagen and Sofia. The role is based in Copenhagen, at least for the initial 3-6 months. While hybrid is a possibility you should expect to work from our Copenhagen office minimum 3 days a week as we build v1.0 working next to the CEO, design partners and product. Curious? Send your CV and let's talk