LLM - a stateless in-memory map/reduce backend service
Vertical LLM - a specialized LLM service optimized for a particular business scenario
RAG (Retrieval Auhmented Retrieval) - an back-end architecture of a service, consisting of a middleware, a database for a full-text or vector serch, and an LLM service
Agents - an architecture, consisting of an LLM, and a middleware that implements business logic, an API, and usually sessions
Multi-agentic system - a microservice implementation of multiple middleware services, and often multiple LLM backends