OpenAI’s ChatGPT Web App Serves a Billion Users Using React Router
The article reverse‑engineers ChatGPT.com’s front‑end, exposing a “boring” stack—React 19, React Router 7 streaming SSR, Tailwind, Radix UI, and TanStack Query—so anyone can start typing instantly, no login. Skipping client‑side rendering, using feature‑flags, massive‑scale CSS, and token‑by‑token streaming lets OpenAI keep latency low while serving about a billion daily users.