oh that's fantastic. I saw a plotly demo many years ago when you sponsored my local PUG, and while it looked cool, I never gave it a chance because I assumed it was just a web service.
Many years ago, indeed it was, but now you can use it and rest easy that your data isn't transiting through our servers unless you install the chart_studio module as well.
I fell victim to this a couple of years back! Sometime later I discovered I'd inadvertently published a public dashboard that I really shouldn't have.
Ouch. That definitely doesn't happen any more since v4 came out two years ago.