Plotly.py is indeed developed primarily by employees of Plotly the company, but it's a 100% free/open-source, MIT licensed library that works totally offline an

Plotly.py is indeed developed primarily by employees of Plotly the company, but it's a 100% free/open-source, MIT licensed library that works totally offline and doesn't depend on any external service or require any kind of registration :) See https://plot.ly/python/is-plotly-free/ https://plot.ly/python/is-plotly-free/ for full details.