SQL Developer is a free integrated development environment provided by Oracle for working with SQL and PL/SQL. It allows users to create, manage, and manipulate databases easily, offering tools for writing and executing queries, debugging code, and managing database objects. With SQL Developer, users can connect to various databases, including Oracle and MySQL, and perform tasks such as data modeling, reporting, and data migration. Its user-friendly interface simplifies database management, making it accessible for both beginners and experienced developers.