I've created an online solitaire platform (https://online-solitaire.com/) that's earning me $10k/m now. It started as a side-project 5 years ago, but I've recently gone full time on it.
It actually started as a Mac app 10 years ago and I choose to create a solitaire game because I had made a string of side-project that I didn't earn any money on, so I wanted to see if I could find a project that would actually generate some side-income.
I did it by scraping the Mac App Store so I could find apps that had a lot of downloads and bad reviews. I figured that if an app had a lot of downloads, but got bad reviews then I could create something better and there would be an audience for it. The app ended up making enough money that I've kept it as a side-hustle for all these years. I've written about how I picked the app here: https://www.indiehackers.com/post/how-i-grew-a-simple-solita....
Can you clarify how it makes 10k/mo? I don't see anywhere on the site where a person could donate/buy something, and I don't see ads. Your download also seems free. How does it actually generate any cash for you?
I built a WordPress plugin and sold it after a few years. I'm currently promoting another. Th answer the original question "how did you come up with the idea?" - I find blue ocean apps that I like and rebuild them, customized for WordPress. My first plugin with a kanban board inspired by Trello. My current plugin is Social Link Pages ( https://sociallinkpages.com ), inspired by Lintree, Carrd, etc.
It actually started as a Mac app 10 years ago and I choose to create a solitaire game because I had made a string of side-project that I didn't earn any money on, so I wanted to see if I could find a project that would actually generate some side-income.
I did it by scraping the Mac App Store so I could find apps that had a lot of downloads and bad reviews. I figured that if an app had a lot of downloads, but got bad reviews then I could create something better and there would be an audience for it. The app ended up making enough money that I've kept it as a side-hustle for all these years. I've written about how I picked the app here: https://www.indiehackers.com/post/how-i-grew-a-simple-solita....