+-------------------+ +-------------------+ +-------------------+ | Front‑End SPA | <---> | API Gateway / | <---> | Content Service | | (React / Vue) | | Auth Middleware| | (Node / Go / .NET)| +-------------------+ +-------------------+ +-------------------+ ^ | | v +-------------------+ +-------------------+ | Auth Service | | Ranking Engine | | (OAuth2 / JWT) | | (Cron + SQL) | +-------------------+ +-------------------+ ^ | | v +-------------------+ +-------------------+ | DB (PostgreSQL) | | CDN (images) | +-------------------+ +-------------------+