Three Architectures for AI Chat: Static Index, Hosted RAG, or Self-Contained Plugin

This article examines three practical approaches to implementing AI chat with vector search capabilities, each optimized for different deployment scenarios: zero-infrastructure static indexing for small documentation sites, enterprise-scale Postgres + pgvector for multi-tenant systems, and a self-contained WordPress plugin. Understanding when to apply each architecture enables teams to balance cost, complexity, and scalability based on their specific infrastructure constraints and growth trajectory.