Dive into mobile app deep linking

Mobile app deep linking is a technology that launches an app and opens a specific page once a user clicks a URL on a web page or in another app. Implementing deep links is a sure way to optimize user experience and increase your conversion rates. With this in mind, here’s how to create a deep link and other useful insights related to the topic.

Why do you need deep linking?

Let’s assume you’ve published a music app. To celebrate the release of a new song, you’ve paid tons of money to run a campaign on a popular website. In your campaign, you feature a brief sample of the song – and you probably want the user to listen to the sample inside of your app rather than on your website, where they would only see the album cover.

In another example, let’s say you want to regain inactive users through a sales campaign. In this campaign, users would be directed to the sale products page in your app with a single click, without having to search for it or manually type a coupon code. Both of these examples are where deep links come into play: deep linking makes these campaigns possible.

Mobile app deep linking brings seamless user experience and can increase your conversion rate and retention rate significantly. If you’d like to learn more about this, take a look at our blog post discussing the effects of deep linking in campaigns.

Why do deep links exist?

As we’ve covered, deep linking makes moving through any kind of journey between web and apps much easier for users. It also gives advertisers a much better chance of converting those users too.

For an example, let's say that we want to run a campaign promoting Christmas gifts to get shoppers on to your e-commerce app. In your campaign, you feature “Christmas gifts” as a category, previewing your stock, but you would like shoppers to view the items on your app as opposed to your website. This is where deep linking comes into play. If the user has the app installed when they click the link the app will open and (in certain cases) will show the product straight away.

Retaining users is a key focus of deep linking. Using deep links keeps users locked into your app. It also has great utility for re-engaging users, and is often a key component of retargeting campaigns. Ultimately, deep linking provides a versatile method of directing users through your ecosystem, creating a better user experience which can increase your sales, conversions and retention rates.

Two types of deep links

There are two kinds of links: default and deferred deep links.

Default

Default deep links only direct users to an app if it’s already installed. If the app is not installed, the link can’t reach the endpoint of an app then an error message is displayed.

Default deep links are useful for retargeting campaigns where an app marketer is solely interested in finding users who have the app installed, and want them to return.

Deferred

Deferred deep links are more complex than default deep links. They can direct users to the App or Play Store if the user does not have the app installed (or to another location, such as the app’s website for more information), and then open the original page that user was directed to.

So, for example, if a user downloads an e-commerce app after clicking an ad for a pair of shoes, but doesn’t have the app installed, they will first be routed to the store for download. When they open the app after install, the product page would be shown.

Deferred deep links are only made possible through a deep linking solution like Adjust’s. They’re created via an SDK integration, and more information on this, click here for Android and here for iOS.

Contextual deep linking?

You may have heard the term contextual deep linking. These refer to links that ostensibly provide additional benefit, in the form of being able to store more information allowing marketers to do more with their content.

Contextual deep links are default or deferred deep links with added parameters marketers can add themselves. Such links don’t exist by themselves.

How to create a deep link

Let’s start with the basics: generating a deeplink. The usual process can be full of pain points and unnecessary back-and-forths between developers and marketers as links must be implemented within the app to point users to their desired destinations.

Additionally, manual deeplink creation can become a huge time sink. It can also increase the chance of human error creeping in. Like any URL — a deeplink doesn’t work if there’s a typo in it, and even the best engineer is prone to occasional typos. Having a solution to automatically create deeplinks can free up time and resources needed that can otherwise be spent on the actual optimization of campaigns and strategy.

Ultimately, you’ll want to look for a tool that is easy to use and automates the link generating process to increase reliability and minimize human-error. Learn more about Adjust’s Deeplink Generator, a tool that provides marketers with a fully-formed deep link URL that works for both App Links (Android) and Universal Links (iOS), greatly reducing the hassle of implementing deep links yourself.

Both scheme-based deep linking (for Android and iOS) and iOS 9+ Universal Link are fully documented, and the basic ideas are quite similar: associate a URL (for scheme-based, youapp://; for universal links, https://yourdomain.com/) with your app. When the URL is clicked, the system will open the app if it’s installed.

But the world isn’t perfect. You’re probably wondering what happens if someone clicks on a deep link URL but doesn’t have my app installed. Unfortunately, they’ll either see an error message or nothing will happen. While there's no direct way to check whether or not an app is present on a device from web, there are few ways to "poll" your app when it exists and send customers to the App Store, to your website, or any other location when it doesn't.

As already stated, scheme-based mobile app deep linking for Android and iOS and iOS 9+ Universal Link are fully documented - so let’s take a look at examples of how they work.

Deep Link implementation for Android

As an Android deep linking example, let’s assume your deep link URL is yourapp://path/, and your App’s bundle ID is com.yourapp.example.

JavaScript solution

A common and old technique to solve this problem is using iframe to load the deep link URL and having a delayed JavaScript to redirect to store:

By doing this, the browser will try to load yourapp://path/ first.

• If your app is installed, then it will be opened and the following JavaScript won’t run.
• If your app is not installed, then nothing will happen while loading yourapp://path/. After 2 seconds, the page will be redirected by the JavaScript to to the Play Store, and the user can install the app from there.

The above code has a little problem, though – after the app is opened and the user switches back to their browser, the JavaScript may continue and redirect them back to the Play Store. So we can do some optimization by checking the time a user switches back to their browser in order to determine whether they need to be redirected to the store or not:

Intent solution

Since Chrome for Android version 25 and later, the above code stopped working according to Chrome documentation. Fortunately, Google provides the Intent URL for a better solution. When a user clicks on the URL intent://path/#Intent;scheme=yourapp;package=com.yourapp.example;end, then

• if the app is installed, it will be opened by Chrome.
• if the app is not installed, Chrome will open Play Store.

Which deep link solution should I use?

The Intent solution is highly recommended because it’s much simpler to implement and the user experience is more seamless. However, it requires browser support, and the Android system is unfortunately so fragmented that there are still plenty old OSes and browsers out there. Moreover, the Android WebView used by tons of apps don’t support Intent URLs by default. The following table shows which solution you should use for mainstream Android browsers: