chat-application-architecture

End-to-end architecture of a conversational AI application in TypeScript with NestJS, Prisma, PostgreSQL and a Nuxt client - performance first (time-to-first-token, fast thread list and open, coalesced streaming writes, responsive long threads), projects that group conversations with shared instructions and reference files, conversation and message-tree data model with edit/regenerate branching, typed message parts, run records and status lifecycle, idempotent sends, server-owned truth versus optimistic client state, request flow, stop/regenerate/edit/retry semantics, attachments, titles, deletion, per-conversation model selection, and instruction layering. Provider-agnostic. Load when designing or reviewing the data model, API, performance, or request flow of a chat application.