I was a regular at the options trading subreddit. Lots of questions about how to modify strategies kept coming up (I also have been thinking about it for a while) so I built https://putcalltheta.com.

Got some buzz when i first announced it but things went cold after that. I still get a few user signups occasionally. Need to do some work on it but my mind is wandering off to other projects.

Edit: lessons learned 1. I probably should have had a mobile version of the webapp at launch. 2. Marketing is hard