Flask is a lightweight Python web framework designed to be simple and easy to use. It is often referred to as a “microframework” because it doesn’t include a lot of built-in tools or libraries. Instead, Flask provides the core functionality needed to build web applications and lets you choose the extensions and libraries you want to add for features like database interaction, user authentication, or form validation.

This design philosophy makes Flask highly flexible and ideal for building small to medium-sized applications, prototypes, and microservices.