Full Stack Engineer

We are hiring a Full Stack Developer To apply, please send your CV and motivation letter to jobs@helionresearch.com About the Company Helion Research is a market research agency specialised in Mystery Shopping & Customer Experience Research, active in over 90 countries for multinational retailers, manufacturers and service providers. We are bringing more of our technology development in-house — and looking for a full-stack developer to help build it. About the Role You will join a small internal development team and work closely with our technical lead, management and business users. Because the team is small, you get real responsibility early: your own components, direct contact with the people who use what you build, and a say in technical decisions. You won't be expected to figure everything out alone. Responsibilities • Build features across our TypeScript stack: React frontends (Vite, TailwindCSS, TanStack Query) and typed backends (Hono, tRPC, Drizzle on PostgreSQL) • Connect those applications to Helion systems, databases and external APIs • Build AI features into the product, such as LLM-supported grading and validation of research data • Help make AI-generated output reliable enough for production use • Take prototypes to production: testing (Vitest, Playwright), documentation, code quality • Try different technical approaches and measure what works Qualifications 1 – 4 yrs experience — ideally Required Skills • Good software-development fundamentals • Experience with full-stack, backend or web application development • Solid TypeScript — used across the entire stack • React • Databases and SQL (we run on PostgreSQL) • Building or integrating APIs • Git / GitHub • Able to read existing code and build reliable new functionality on top of it • Genuine interest in building with LLMs — work, side projects, studies or open source • Basic understanding of LLM applications: inference cost/time, and how RAG fits together • Comfortable working primarily from our Antwerp office Preferred Skills • Bun, Vite, TailwindCSS, Hono, tRPC, Drizzle, Zod, TanStack Query • Cloudflare Workers or other serverless platforms • Testing with Vitest, Playwright or similar • Docker • Authentication, permissions & application security • PDF or image processing Pay range and compensation package Salary based on experience + extra-legal benefits Office in city centre of Antwerp 2 days work from home Full-time, permanent position, Antwerp, Belgium Equal Opportunity Statement We are committed to diversity and inclusivity in our hiring practices. Apply: send CV + motivation to jobs@helionresearch.com