CodePen 2.0 sends your keystrokes to its servers before you save
Apparently CodePen 2.0 sends data to their servers as you type
A Hacker News user reports that CodePen 2.0 transmits editor input to its servers almost immediately, even before saving. They tested by typing a unique marker into index.html, and it appeared in the generated preview HTML without saving. This raises privacy concerns: any secrets typed by mistake may be compromised even if the pen is never published.
Thus, if you ever entered some secrets in there by mistake consider them compromized even if you did not publish/save the pen.