Online databases are digital repositories that allow users to store, manage, and retrieve data over the internet. They provide a structured way to organize information, making it accessible from anywhere with an internet connection. Examples include MySQL, MongoDB, and Firebase, which cater to various data needs and applications. These databases are essential for businesses and developers, enabling efficient data handling and collaboration. They often come with features like scalability, security, and backup options, which are crucial for maintaining data integrity. As technology evolves, online databases continue to play a vital role in the digital landscape.