Senior Full Stack Developer

ppDelta Labs uses AI to simulate and predict consumer behaviour at scale. We build Elaiia, a simulation engine that generates AI Twins - intelligent synthetic agents that mirror real consumer populations. Our clients use Elaiia to simulate customer decisions before committing to them: pricing strategies, product launches, campaign messaging, channel allocation. We replace surveys, focus groups, and intuition with simulation-based evidence. /p pWe're a small, focused team and we intend to stay that way. We give people ownership, trust, and the autonomy to do their best work. We work with urgency and intellectual honesty and expect new team members to match our pace. We seek individuals who are curious, rigorous, and want their work to have demonstrable impact. If you're drawn to the idea of a small team building something that hasn't existed before, let's build together. /p h3ABOUT THE ROLE /h3 pAs a Full Stack Developer at Delta Labs, you will design and build the systems that power Elaiia's simulation platform. The Engineering team owns the full stack, from database schema to production UI, and is responsible for making Elaiia fast, reliable, and scalable. /p h3THE STACK /h3 pA modern TypeScript frontend stack built on Next.js and React, backed by PostgreSQL and a set of Python microservices. Long-running study workflows are orchestrated as durable background jobs. OpenAI, Anthropic and Google Gemini are deeply integrated into the product layer, with LangGraph agents and full LLM tracing and evals. Deployed on Vercel and Microsoft Azure. /p h3RESPONSIBILITIES /h3 ul liDesign and build production features across the full stack, from data model to UI /li liIntegrate LLM APIs into production workflows: prompt pipelines, structured outputs, token optimization, and reliability at scale /li liBuild and operate long-running, multi-step simulation workflows - durable jobs that run for minutes or hours and cannot silently fail /li liTreat LLM quality as measurable: tracing, evals, and regression checks on the AI paths you own /li liOwn entire features end-to-end and take responsibility for their performance, quality, and correctness /li liCollaborate with the research team to transition experimental AI capabilities - statistical persona models, agent architectures - into production-grade systems /li liImprove and extend the platform architecture as simulation workloads grow in complexity and volume /li liShip continuously to maintain the pace the company needs /li /ul h3YOU MAY BE A FIT IF /h3 ul liYou have 4+ years of experience shipping production web applications in TypeScript /li liYou are strong in the modern React/Next.js ecosystem, and care about code quality, performance, and maintainability /li liYou are comfortable reading and writing Python, or ready to be - a meaningful part of our backend is Python services /li liYou have designed relational database schemas that hold up under real-world scale and complexity /li liYou have worked with or are deeply curious about LLM integration - prompt engineering, structured outputs, retrieval-augmented generation, agent architectures /li liYou use AI tools as a core part of your development workflow and consider AI-assisted engineering the standard, not optional /li liYou are comfortable working with ambiguity and incomplete specifications /li liYou communicate clearly about technical trade-offs and write useful documentation /li /ul h3STRONG CANDIDATES MAY ALSO /h3 ul liHave built AI-powered features used by real customers in production /li liHave shipped LLM features with real evaluation and observability behind them, not just prompts that looked good in review /li liHave built asynchronous, long-running job pipelines and know how they fail /li liHave worked on multi-tenant including enterprise SSO /li liHave worked across both Vercel and cloud infrastructure like Azure /li liHave worked in a high-velocity early-stage environment /li /ul h3LOCATION /h3 pThis role is based in Switzerland. We work from Zürich and meet regularly in person. Candidates should be based in Switzerland or open to relocation. /p h3BENEFITS /h3 pWe offer a competitive salary, potential equity participation, and the opportunity to build a company from its earliest stages. Delta Labs is an equal opportunity employer. We welcome applications from all backgrounds /p /p