Blitz.js is a React framework that streamlines the process of building full-stack, monolithic applications by integrating simplicity and conventions reminiscent of earlier web frameworks like Rails, while maintaining the modern components of JSX and client-side rendering. It simplifies development by eliminating the need to create APIs for data fetching, supporting both client-side and server-side rendering, and providing a CLI for code scaffolding similar to Rails. Blitz is built on Next.js, allowing developers to leverage its API for meta tags and navigation, and it fully supports TypeScript with end-to-end typing. Default database configuration with SQLite and Prisma 2 can be customized to use other databases like PostgreSQL. Despite being in its alpha stage with limited documentation, Blitz offers a promising solution for developers seeking to deploy applications quickly while gradually integrating advanced technologies.