WebSQL is a web API that allows developers to store and manage structured data in a relational database directly within a web browser. It uses a SQL-like syntax for querying and manipulating data, making it easier for developers familiar with traditional databases to work with client-side storage. Although WebSQL was supported by some browsers, it was never standardized and has been deprecated in favor of IndexedDB, which offers a more flexible and powerful way to handle large amounts of data. As a result, developers are encouraged to use IndexedDB for new projects to ensure better compatibility and future support.