SQLite is a unique and widely used database engine that, unlike traditional client-server systems like MySQL or PostgreSQL, is serverless, self-contained, and requires zero configuration. Instead of running as a separate server process, the entire SQL database engine is embedded as a library directly within an application, and the complete database—including tables, indexes, and data—is stored as a single cross-platform file on the host machine. This lightweight, transactional, and highly reliable design makes SQLite an extremely popular choice for data storage in mobile applications, web browsers, embedded systems, and any scenario where a simple and portable database solution is needed without the overhead of a dedicated server.