When it comes to deep link, not many people know what it is. It’s the unsung hero of technology world. Yet people use it everyday without realizing its existence, or maybe don’t know it has a name. In part 1 of this Deep Link series, you will get some basic ideas about what is deep link and how it is applied on mobile.
So what is deep link?
Deep linking is a methodology for launching a native mobile application via a link.
Deep link does exactly what it says: take users deep inside a website/application with a link. On desktop, deep linking is the use of a hyperlink that links to a specific content inside a website (e.g., “http://example.com/path/page”), rather than the website’s homepage (e.g., “http://example.com/”). On mobile, deep linking use a uniform resource identifier (URI) that links to a specific location within a mobile app instead of just launching the app. In this series, we only focus on mobile deep linking.
So you are browsing the Internet on your mobile. You search “Facebook” on Google and the first result points to Facebook’s home page. You tap on that link and instead of being redirected to Facebook’s home page, the Facebook app on your mobile opens. That’s basically how mobile deep linking works.
Enabling deeplinking for a mobile application will allow you to invoke deeplinks that open an app and launch specific, defined screens within the app, such as the homepage, product pages, and shopping cart, much as you would on a website.
Deeplinking is especially useful for promotional efforts because it allows you and any third party to open the app when a link is clicked, rather than driving to a website or to your app’s listing on the iOS App Store or Google Play.
There are 3 types of deep links
1. Traditional deep links
Traditional deep links can route users to app content as long as the app is already installed when the link is opened. This means traditional deep links don’t work if the user doesn’t have the app, and will show either an error or a fallback page.
2. Deferred deep links
Deferred deep links can route users to content even if the app is not installed when the link is opened. The link will first redirect to the App Store or Play Store to download the app, and then take the user to the specific “deferred” content immediately after first launch.
3. Contextual deep links
Contextual deep links have all the functionality of deferred deep links, plus much more. Contextual deep links store information about where a user wants to go, where the link was clicked, who originally shared the link, and an almost unlimited amount of custom data.
Contextual links add value for both app developers and users. App developers can build powerful features beyond just simple content linking, including personalized welcomes (where you see your friend’s recommendation in the app if they share an item with you) and referral programs. App users benefit because apps can provide better experiences and more relevant information.
Custom URI schemes were the original form of deep linking for mobile apps. They are like creating a “private internet” for your app, with links that look like myapp://path/to/content. The advantage of custom URI schemes is they are easy to set up and most apps already have one. The disadvantage is a user’s device only knows about this “private internet” if the corresponding app is already installed, and there is no graceful fallback option by default.
This is still the primary approach to deep linking on Android, but Apple began blocking this approach on iOS in 2015 with the release of Universal Links.
Apple iOS Universal Links
Apple introduced Universal Links in iOS 9 as a solution to the lack of graceful fallback functionality in custom URI scheme deep links. Universal Links are standard web links (http://mydomain.com) that point to both a web page and a piece of content inside an app. When a Universal Link is opened, iOS checks to see if any installed device is registered for that domain. If so, the app is launched immediately without ever loading the web page. If not, the web URL (which can be a simple redirect to the App Store) is loaded in Safari.
A study of the thousands of apps on the Branch platform found that Universal Links increased conversion to open by 40%.
Google built App Links as the Android equivalent to iOS Universal Links, and they operate in a very similar way: a standard web link that points to both a web page and a piece of content inside an app. This results in a smoother user experience, but since custom URI schemes are still fully supported by every version of Android, App Links have seen very low adoption.
Facebook App Links
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.
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.
Facebook now prefers to keep users inside its platform, and has removed the App Links routing engine from everywhere except the main Android app. Since Facebook also blocks iOS Universal Links, this leaves no reliable way to open third-party apps from Facebook or Messenger on iOS. Branch has implemented a solution to help work around these limitations.
Till this point, we’ve got a basic understanding of what deep link is and types of deep links. In Part 2, we will discover how deep links can help in terms of marketing.