# develop in python 2 to start
pyenv local 2.7.13 
pyenv activate my-project-2.7
pip install -r requirements.txt 
pip freeze > requirements.lock

# switch to python 3
pyenv local 3.7.2
pyenv activate my-project-3.7
pip install -r requirements.txt
pip freeze > requirements.lock

I'm still not happy with this. I failed to read the docs and understand the difference between "libraries and applications". I'm going add a -1 to "pipenv is for humans". I get that package distribution is hard. So is developing for multiple platforms. But it seems like there is a simple question/answer here: "Can I have two (or N) environments side by side within the same code directory?" It seems like `tox` might support this concept, but we've only added more to the complicated picture:  However, it advertises "switch between python versions and virtual environments so you can build docs, run tests, etc." which seems like a good thing to do if your supporting multiple versions. I'm also tempted to just delete `pipenv` and go old school: # develop in python 2 to start pyenv local 2.7.13 pyenv activate my-project-2.7 pip install -r requirements.txt pip freeze > requirements.lock # switch to python 3 pyenv local 3.7.2 pyenv activate my-project-3.7 pip install -r requirements.txt pip freeze > requirements.lock And now I'm back to using virtualenvwrapper......