Docker is a platform for application containerization. Containerization allows developers to package an application together with all its dependencies into a container and then run it consistently on any system that supports Docker.
Docker was originally developed by Docker, Inc. in 2013. It began as an internal project aimed at improving developer workflows, but its potential was quickly recognized by the industry, and Docker soon became the de facto standard for container-based application deployment.
Today, Docker is widely used across the IT industry, including by a large share of enterprise companies, and it plays a central role in modern DevOps and cloud-native infrastructure. According to Docker, Inc., millions of developers use the platform worldwide, and it has become one of the most influential technologies in the container ecosystem.