Build a secure RAG API

About This Tutorial Series

What You'll Learn

• Explain the ingest, retrieve and generate path of a RAG API and identify the points where a multi-tenant support assistant can leak data or mislead users, so the reader knows what the series will buil
• Build a Node.js 24 service that chunks tenant documents, stores embeddings in PostgreSQL 17 with pgvector 0.8 and an HNSW index, and returns the top-k similar chunks for a query.
• Add an /answer endpoint that assembles retrieved chunks into a bounded prompt, calls an LLM through a provider interface, returns citations and declines to answer when retrieval finds nothing relevant
• Propagate the authenticated caller's tenant and roles from a verified JWT into each database session, enforce isolation with PostgreSQL row-level security and document ACLs inside the filtered vector
• Build a golden dataset and an eval runner that measures retrieval recall@k, answer groundedness and cross-tenant isolation, and wire it into CI so a change that degrades quality or leaks data fails th

Prerequisites

• Before you start

  Node.js and REST APIs, no prior RAG experience.