This is, historically, one of my favorite iOS topics because of the ridiculous number of solutions to it: What if I haven’t published the app before? What if I don’t want it to go to iTunes?! Can I link without redirects??
So here’s the final solution for every conceivable situation, only very recently solved by Apple. (Finally!) Where a specific name is necessary I’ll use Task List Pro and Rapture In Venice as the example since each is a messy name with spaces, but you should swap in your own app or publisher name, obviously.
Linking to an app via App Store/iTunes:
Linking to developer/author via App Store/iTunes:
Is the app is already in the App Store, this handy Apple page will generate links for you that work in a browser when on desktop:
Apple has let this be an “issue” for too long, fostering endless threads about links that redirect and what to do about punctuations. Finally, they made their Link Maker, but that only led to more confusion because it doesn’t address apps that are not yet in the App Store. (What do you do if you’re creating v1.0 of your app?) Contrast this with Android where things have always been much simpler:
Google may have taken a long time to get their UI right, and they still can’t solve their versioning problem, but they’ve always gotten developer-oriented things like this right at least.