App Links: Facebook’s Proposal For Routing Traffic Between Apps Explained

Two weeks ago, Facebook announced App Links, a proposed standard for routing traffic between mobile applications. If the app developer community adopts the App Links standard, there will finally be a cross-platform standard for linking between apps. It will also help drive significant new revenue for Facebook’s ad products.

FacebookAudienceNetwork650Two weeks ago, Facebook announced App Links, a proposed standard for routing traffic between mobile applications. If the app developer community adopts the App Links standard, there will finally be a cross-platform standard for linking between apps. It will also help drive significant new revenue for Facebook’s ad products.

There has been a fair amount of confusion about what App Links means, so let’s clear the air first.

App Links is a proposal released by Facebook that shows app developers how to send users clicking links within their apps to the apps corresponding to the destinations in the links. This is hard to grasp, so let’s discuss an example use case from end to end:

An email mobile app like Mailbox can implement the App Links standard in its app itself, or by using an open-source library Facebook released called Bolts.

When a user opens the Mailbox app on his or her phone, the real process begins.

The user clicks on a link in an email, like a link to a Hulu TV show.

The Mailbox app checks if the Hulu website header has App Links tags showing deep links for Hulu iOS, Android, or Windows Phone apps (Mailbox can also check an App Link Index through a Facebook application-programming interface for App Link tags).

Mailbox then tries to send the user to deep links found in the App Links header tags on Hulu’s website for that user’s device.

If the user has the Hulu app installed, Mailbox sends him or her to the correct deep link.

If the user does not have the Hulu app installed, Mailbox sends him or her to the Hulu website.

Essentially, when a user clicks a link and the referrer app and the destination app both support the App Links standard, the user will be sent to the Hulu app if they have it installed, or to the website if they do not.

App Links Still In Early Days

There are a few important things to note. Both the referrer and destination apps must support the App Links standard in order for the user to be sent to the destination app. At launch, Facebook, Mailbox, and Spotify have implemented the standard in their apps, and 11 destination websites support the App Link tags. So today, when users click on links in Facebook, Mailbox, and Spotify for the 11 destination sites that support App Links, the user will be deep-linked if the user has the destination app on his or her smartphone.

While the App Links standard only works for specific use cases today, Facebook hopes to grow its adoption so that it will eventually work for all links on mobile. In order to make this standard ubiquitous, Facebook will need app developers to support it. Leveraging Parse’s developer-relations capabilities should enable the social network to accomplish this. However, it will also need major players like Google and Yahoo to support App Links in order to ensure that when any link is clicked in Gmail, Yahoo Mail, or popular apps, the App Links standard is leveraged. Getting Google, Yahoo, and other major players to support App Links could prove more challenging, however.

Another important note is that the App Links standard is a proposal for how to send users clicking on links in one app to a destination app. It does not discuss users clicking on mobile websites and sending them into destination apps. For example, if a user clicked on a Hulu link on the Facebook mobile website, the App Links proposal does not provide a description for linking into the Hulu app. This makes the proposal extremely useful for app-to-app linking, but less so for Web-to-app linking. In order to let marketers send one link that works for both app-to-app and Web-to-app linking, URX released omnilinks, a link that works everywhere today.

Why Does App-To-App Linking Matter To Facebook?

So, why is Facebook proposing a standard for how to link from app to app? There is a clear need for a single standard for how apps link to one another so developers can easily link to each other’s apps. By releasing open-source projects to make it easier for developers to link to other apps, Facebook is helping kick-start the movement. In addition, App Links will help advance Facebook’s ad business.