.. _python3-support: Python 3 Support ================ Flask and all of its dependencies support Python 3 so you can in theory start working on it already. There are however a few things you should be aware of before you start using Python 3 for your next project. If you want to use Flask with Python 3 you will need to use Python 3.3 or higher. 3.2 and older are *not* supported. In addition to that you need to use the latest and greatest versions of `itsdangerous`, `Jinja2` and `Werkzeug`. Flask 0.10 and Werkzeug 0.9 were the first versions to introduce Python 3 support. Some of the decisions made in regards to unicode and byte utilization on Python 3 make it hard to write low level code. This mainly affects WSGI middlewares and interacting with the WSGI provided information. Werkzeug wraps all that information in high-level helpers but some of those were specifically added for the Python 3 support and are quite new. Unless you require absolute compatibility, you should be fine with Python 3 nowadays. Most libraries and Flask extensions have been ported by now and using Flask with Python 3 is generally a smooth ride. However, keep in mind that most libraries (including Werkzeug and Flask) might not quite as stable on Python 3 yet. You might therefore sometimes run into bugs that are usually encoding-related. The majority of the upgrade pain is in the lower-level libararies like Flask and Werkzeug and not in the actual high-level application code. For instance all of the Flask examples that are in the Flask repository work out of the box on both 2.x and 3.x and did not require a single line of code changed.