We are hiring a Full Stack Developer

To apply, please send your CV and motivation letter to [email protected]

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 [email protected]

📌 Full stack engineer (España)
🏢 Helion Market Research
📍 España