Technical notes
What I learn building products end to end: AI, public data, architecture and open source.
Legalize on Xataka, 14 countries and the first RAG on legislation
Xataka features Legalize, the open source community takes it to 14 countries, I launch a public API, and someone has already built a RAG on top of the data.
ProjectMar 28, 2026Legalize, GStack and 140 comments on Hacker News in three hours
How I discovered GStack, launched Legalize (version-controlled legislation with Git) and ended up with 140 comments on Hacker News in three hours.
OpinionMar 27, 2026AI will amplify inequality. Quartier is my way of doing something about it
AI will multiply the productivity of those who use it, leaving behind those who don't. Quartier is an open source toolkit so anyone can start a web redesign business using AI.
ArchitectureMar 24, 2026How I built Boletín Claro: architecture of a SaaS on official bulletins
Technical deep dive into Boletin Claro's architecture: a SaaS that processes Spanish official bulletins using Go, Python, React and Cloud Run.
Data EngineeringMar 24, 2026Scraping official bulletins in Spain: BOE, BDNS and 20 regional gazettes
How to extract data from Spain's BOE, BDNS, and regional official bulletins programmatically: XML parsing, REST APIs, PDF handling, and idempotency strategies.
AI / NLPMar 24, 2026Embeddings and semantic search over official bulletins
How to implement semantic search with embeddings over legal and administrative text: indexing pipeline, chunking, reranking, and real-world examples.
AI / LLMsMar 24, 2026How I use AI to summarize official bulletins
Prompt engineering, smart filtering, and cost optimization: how I use LLMs to summarize hundreds of official bulletin entries every day.