Alexandre Castro

I'm a backend and AI engineer with nine years of experience, moving toward backend and DevOps work. I spent seven of those years in QA, and I have an educational background in Cognitive Science.

I'm a Backend & AI Engineer based in Copenhagen. Right now I build the infrastructure behind an Agentic RAG system at Caliber (data ingestion, web scraping, search API integrations, the retrieval pipeline itself).

Before that, I spent over two years as the sole Product Engineer for Neurons' public API. I led the v2.0 rebuild, which helped scale the platform from 7 to 20+ enterprise clients and grow ARR from €250K to over €1M. I also built the API sandbox and documentation that became one of Sales' most effective tools for closing new accounts.

My path here wasn't linear. I spent seven years in QA and test automation, often as the first dedicated tester at a company, building quality infrastructure from nothing at places like Productboard, Pento, and Smartlook. That background is still how I build today: tested, documented, and made to survive contact with real users.

I hold a degree in Pharmacy and completed graduate coursework in Cognitive Science (machine learning, NLP, deep learning). Less of a detour than it sounds. Both trained me to think carefully about complex systems before I touch them.

These days I'm looking for backend and/or DevOps roles, somewhere I can keep building infrastructure people depend on. I've also been teaching myself security and DevSecOps lately (ISO 42001, API security), and I'd like that to become a bigger part of what I build next.