CollabHub is a real-time SaaS collaboration platform unifying document editing and team communication in one system. I built a full-stack architecture using a NestJS backend with Socket.io for real-time sync, Redis caching for performance, and BullMQ for background processing of workspace invites. The web frontend uses Next.js with Mantine UI, while the mobile version is built with React Native, Expo, and Tamagui for a shared cross-platform experience.