I Built a Multi-Provider AI Chat App with Django and React — Here's What Actually Happened

The Idea The core idea was simple: a ChatGPT-like interface backed by free-tier AI APIs, with Google login, persistent chat history, and real-time streaming. The twist was multi-provider routing — if Groq's free quota runs out mid-day, the app silently falls back to Gemini, then Mistral. The user never sees an error. They just keep chatting. Stack I chose: Django 6 + Django REST Framework on the backend React 19 + TypeScript + Tailwind CSS v4 on the frontend Groq (Llama 3.3 70B), Google Gemini 2.0 Flash, Mistral Small for AI Google OAuth 2.0 for auth Render (backend) + Vercel (frontend) + Neon (Neon) — all free tier Starting with Auth I wanted Google OAuth because it's frictionless for users. No password forms, no email verification — just "Sign in with Google" and you're in. The standard django-allauth approach assumes a server-side redirect flow — Google redirects back to your Django backend, and Django sets a session cookie. That doesn't work cleanly when your frontend is a separate