Tech Ocean

Oct 5, 2026 · Backend Development

Building an AI Chat Backend MVP with FastAPI: Auth, Tools & SSE Streaming

This article walks through building a production-ready AI chat backend using FastAPI, covering user authentication with JWT, per-user chat isolation, local tool calling (time, date diff, calculator), SSE streaming with proper connection handling, and transactional message persistence that leaves no partial records on errors or client disconnects.