Flask

Flask is a micro web framework written in Python, part of the Pallets ecosystem alongside Click and Jinja2. Unlike Django, Flask ships with only the essentials — routing, request handling, and a templating engine — leaving the rest to you. That minimal footprint makes it a strong choice for REST APIs, lightweight web apps, and prototypes where you want full control over the stack.

The framework’s design philosophy is “one drop of water.” You start with a single file and add only what you need: SQLAlchemy for the database layer, Flask-Login for authentication, or Flask-RESTful for APIs. This composability is why Flask remains widely used in data science workflows, where teams often need a quick web interface around a model without the overhead of a full framework.

Flask’s documentation is thorough and beginner-friendly, and its ecosystem of extensions is mature. For teams building microservices or internal tooling, Flask’s simplicity and predictable behaviour make it a reliable foundation.