> For the complete documentation index, see [llms.txt](https://vitalys.gitbook.io/vitalys/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vitalys.gitbook.io/vitalys/technology-stack/backend.md).

# Backend

* **Core Framework**: Node.js with Express (Microservice architecture)
* **Database**: PostgreSQL for structured data, with Redis for caching active user states
* **Authentication**: Firebase (for email-based Web2 login) + Web3Auth (for wallet onboarding post-registration)
* **Real-Time Updates**: Socket.IO for live chats, typing indicators, and event triggers