Deep links look exactly the same as usual links, but they are used in mobile campaigns. When clicked, instead of opening a browser with the URL, just like a usual link, they open an application on the mobile device and take the user to the specified area of it.
What are deep links?
A prerequisite of using deep links is that they need to be registered with Google and/or Apple. This is needed because the Android/iOS operation systems need to be able to handle the URLs as deep links and open the apps, and to achieve this they check the links clicked against the list of registered deep links. For more information, see Creating a Trackable Deep Link for Mobile in Email.
A typical use case
For example, let's say you are a game developer and you have a game installed on your customers' phone. You would like to draw your customers' attention to a new feature in the game.
To do this, you create a campaign for all users and insert a deep link in it. The link will look something like this: http://game.com/news/new_feature. You have previously registered the app called "game" with Apple and/or Google and added "news" as a part of the app.
Thus, when they click the link on the mobile device, it opens the app and takes the customer to the 'News' section, where the new feature is introduced.
Adding trackable deep links
In case of template-based emails, when adding the link to an element the link editor window shows.
In block-based emails, the pop-up window is different.
The deep links in the above examples will open the app called "example" on the customer's mobile device, open the "shop" part of it and show item number "119".