App Links is an open standard to deep link to content in your app. When someone using your app shares content to Facebook or another App Links-enabled app you can create a link that makes it possible to jump back into your app from that piece of content. App Links work by adding metadata to existing URLs on the web so that they can be consumed by your app.
The Facebook's app for iOS and Android support App Links today. When the Facebook app comes across a link that supports App Links it will launch your app with the right information so someone can see the content immediately and quickly.
1. A person clicks on a story on Facebook
If someone shares a story on Facebook with content from your app, people can click on the story to view the content in your app. The URL shared to Facebook contains App Link metadata.
2. Facebook app looks up the URL to see if it supports App Links
Once someone clicks on a story, the Facebook App does a lookup to see if the content supports App Links. if it does, the Facebook App takes people to your content, either in a web view or by launching your app and linking to the content, depending on the following criteria:
App Links has the following requirements:
It's possible for any app to do what the Facebook app does and add support to launch other apps based on App Links. If you've got an app where people want to click through to links instead of just going to inbound links, we've also provided a document that covers how to add support for the outbound navigation protocol to your app.