When you are listening music on Spotify, usually you are sharing it publicly.
Earlier this week, I noticed that you cannot start Spotify with private session mode enabled. After googling for a solution, I found this answer from Spotify team.
Applescript for the rescue!
On OSX, you can automate many tasks with Applescript. Like opening an application, clicking a menu item etc. And also if developers provided an Applescript API, you can do a lot more (like changing song or getting song title on Spotify).
I thought that, I can write an Applescript code for starting Spotify with private session. And it worked!
Here is the code, you can use Applescript Editor tool and create an application from this code.
activate application "Spotify" delay 2 tell application "System Events" to tell process "Spotify" click menu item "Private Session" of menu 1 of menu bar item "Spotify" of menu bar 1 end tell
Here you can watch demo video, I created an application file from Applescript code and it works perfectly.