Build a Serverless RAG Engine for $0

Master modern AI architecture with Node.js, Gemini 2.5, and Cloudflare R2 👉 Get the Source Code & Template Here 👉 Read the full tutorial here Introduction: The Problem with "Toy" RAG Apps Most RAG tutorials skip the hard parts that actually matter in production: No security model: Users can access each other's private data. Naive file handling: Large uploads crash your Node.js server. Expensive infra: AWS egress fees and managed vector DBs drain your wallet. Blocking operations: Processing files freezes your entire API. We are going to solve all of these using a production-proven architecture. The $0 Tech Stack Every piece of this stack has a generous free tier: Cloudflare R2: S3-compatible storage with zero egress fees . Gemini 2.5 Flash: High-performance LLM with a free tier of 15 requests/minute. PostgreSQL + pgvector: Battle-tested database with native vector support. BullMQ: Redis-backed job queue to handle heavy processing in the background. Step 1: Understanding the Architecture