If I develop an app and publish it on AppStore will it be counted as an extracurricular and if I do it for a company will it be a good extracurricular or strong one?
Developing an app is certainly an extracurricular! How impressive it is depends on the skills required and the results. The more advanced the skills required, the stronger it will be. The more downloads and higher ratings, the better as well. If you work for a company to develop it, that is also great. Just make sure define its impact though - how is the company using the app? What does it do? What skills did you use to develop it?
Also be sure to quantify your activity in the Common app as much as possible, and explain it so anyone can understand it. You may have to provide more background since it's not a common activity and requires technical skills.
Best of luck!
Whether developing and publishing an app is a good or strong EC depends on the app and how much traction it has. For example, if you created a COVID-19 tracing app and there were 100,000 users or more I'd say the reader might download it on their iPhone and see if it was any good. If it is just one of the millions of apps that is a novelty, then I don't think it's going to be that strong of an activity. I would say the same thing if you said you were a DJ and published your own music on iTunes. If you had 100,000 plus downloads, then you are legit. Otherwise, you are just like millions of other rising stars who are experimenting with their craft.
Developing an App is a great idea to display that you are creative, innovative, and self-driven. I would definitely encourage you to do it. If you don't mind me asking, how do you plan to develop it? Wouldn't you have to invest a lot of money to create it and then publish it on AppStore?
If it is something that you genuinely want to do and are interested in I say go for it. Every thing you do is important. I think it will count as an extracurricular of course and if it gains popularity then that's an added bonus. But, you shoudn't do it just for the sake of putting on your college applications. You should do it because it is something you would enjoy spending time to develop. Don't do it as a chore because you feel like it will up your chances of getting into the school you want. Do things that fulfil you, that you are interested in and that you enjoy.
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