Docker is a tool designed to make it easier to create, deploy, and run applications by using containers. Containers allow a developer to package up an application with all of the parts it needs, such as libraries and other dependencies, and ship it all out as one package. Using Docker, you can quickly and easily deploy applications in a consistent and reliable manner, regardless of the environment. This makes it easier for developers to create and test applications, and for operations teams to manage and deploy applications in production. Docker also makes it easier to scale applications, since you can deploy multiple instances of a containerized application and load balance traffic between them. This makes it easier to handle increases in traffic and demand for your application. Overall, Docker is a powerful tool that can help you develop, deploy, and manage applications more efficiently and effectively.