Is it possible to use Facebook App Links with email and pass through App Store install? - ios

Question

I am planning to use app link from FBSDK to invite using my iOS app via email.
I know if my iOS app was installed on the device it will be opened when I select the link and handle invite token in URL.
But how about if my app was not installed?
After user install it from App Store can I handle invite token also?
Hope anyone used to work with this scenario can help me.

Answer 1

There are a lot of reasons why what you're trying to do won't come out the way you want it to. Let's dive in...
App Links don't work anymore
Facebook created App Links in 2014 as an open standard to solve the limitations of URI scheme deep links. App Links have two main components:
A set of meta tags to add to the web page destination of a standard http:// link. These tags specify the custom URI scheme location of corresponding content inside the native app, and the behavior that should occur if the app is not installed.
A routing engine for use inside apps that support opening links. This engine checks the destination URL for App Links tags before opening it, and then launches the corresponding app or executes the specified fallback behavior.
App Links were supposed to be an open-source standard to change the world, making app-to-app deep linking simple and universal. Unfortunately Facebook has decided they actually don't want that world (it's much better for them to keep users inside the Facebook app — see Instant Articles if you don't believe me), meaning the App Links standard is essentially dead. It's no longer supported on the iOS Facebook app, and Applinks.org isn't even a separate website now.
App Links were not designed to work with email (or essentially any app except Facebook)
Even if it were still supported by Facebook, the App Links standard has a critical flaw: it requires work by both the origin and destination apps. While the meta tags component saw wide adoption, the only major implementations of the routing engine were in the core Facebook and Messenger apps.
To function as you want, where deep linking can occur from links in emails, the routing engine component would need to be implemented in any email app where your link could possibly be clicked. This was never going to happen for apps like the default iOS Mail app from Apple, or the Gmail app, for example.
App Links had no meaningful support for deferred deep linking
Deferred Deep Linking (Deep Linking refers to using a link to open your app directly to a specific piece of content, and Deferred means that it works even if the app isn't installed first) requires a remote server to close the loop. You can build this yourself, but you really shouldn't for a lot of reasons, not the least of which being you have more important things to do. You'll notice that neither of the two App Links components included a remove server to retain link data through install, so deferred deep linking was never properly supported in the core App Links standard. Facebook ads make use of the partial support for deferred deep linking offered by the FBSDK in conjunction with App Links, but this only works when the link/ad is clicked within a Facebook app and the receiving app has the FBSDK integrated.
Deferred deep linking is tough anyway
Moving on from App Links, deferred deep linking is still complicated. URL schemes don't work, because they always fail with an error if the app isn't installed. Apple's newer Universal Links in iOS 9+ get closer in that they at least don't trigger an error if the app isn't installed, but you'd still have to handle redirecting the user from your website to the App Store. You can't pass context through to the app after install with Universal Links, so you wouldn't be able to send the user to the correct item, and they actually aren't supported in a lot of places.
Deep linking out of email on iOS is very hard
Almost all email links involve some sort of click tracking, which is always implemented as a link wrapping redirect. This isn't technically a problem if the user doesn't have your app installed, but if they do, Universal Links don't work with wrapped links. If you're building it yourself, you'll either need to completely disable click tracking in your emails, or accept that deep links won't work there.
Bottom Line
App Links were never the solution you needed. A free service like Branch.io (full disclosure: they're so awesome I work with them) or Firebase Dynamic Links is what you need. Both services support deferred deep linking, out of Facebook or almost any email app. Branch is more powerful and offers far more features, and works with major email senders to offer a solution for deep linked email (the only one on the market today).