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