pallets

Flask is a lightweight Python WSGI web framework that makes it quick to build web applications with minimal setup while scaling smoothly to complex apps.

Click is a Python command line interface creation kit from the Pallets organization, composing beautiful CLIs with minimal code through decorators, with arbitrary command nesting, automatic help pages, and lazy subcommand loading.

Jinja is a fast, expressive, and extensible Python template engine that renders data into final documents like HTML using Python-like placeholders.

MarkupSafe is a Python escaping library from Pallets that provides text objects safe for HTML and XML, auto-escaping special characters to mitigate injection attacks; it is the foundation under Jinja2 templates.