That's fair. I only have my experience to draw from, but I've personally found it very straight forward. Gevent said it looks like they're supporting Python3 a

That's fair. I only have my experience to draw from, but I've personally found it very straight forward. Gevent said it looks like they're supporting Python3 as of the 1.1 release - http://www.gevent.org/whatsnew_1_1.html http://www.gevent.org/whatsnew_1_1.html I've used requests with Python3 quite a bit.. I have no idea why it's not listed as supported on the WoS, but their page shows it as working since 2012. https://pypi.python.org/pypi/requests/ https://pypi.python.org/pypi/requests/ Protobugs looks like it's now Py3 compatible, per the devs- https://github.com/google/protobuf/issues/646 https://github.com/google/protobuf/issues/646 ThriftPy has supported Python3 for a while (although ThriftPy is slower than the official lib). Apache Thrift has recently begun working with Python3 as well, however (https://issues.apache.org/jira/browse/THRIFT-1857 https://issues.apache.org/jira/browse/THRIFT-1857) I run Ansible/etc in their own virtualenvs, so they aren't part of system python for me, but you're right - I did have to write an Ansible module recently, and I recall that I did have to use Py2. The only major package I recall having a problem with was PIL - Eventually I moved to Pillow as a drop-in replacement.