A micro-framework for Python based on Werkzeug, Jinja 2 and good intentions

Flask is called a “micro-framework” because the idea to keep the core simple but extensible. There is no database abstraction layer, no form validation or anything else where different libraries already exist that can handle that. However Flask knows the concept of extensions that can add this functionality into your application as if it was implemented in Flask itself. There are currently extensions for object relational mappers, form validation, upload handling, various open authentication technologies and more. Python 3 version.