Instant Apps: Build Fast, Lightweight Mobile Experiences

1. Instant "Try" experience in the Play Store

Instant experiences are shown using a Try now button in the Play Store (as shown in Figure 1). This type of experience is typically a smaller trial version of your app or game created with the goal of driving installs. For example, game developers may want to build the first level of their game as an instant experience and then prompt users to install the full game.

2. "Instant play" full game experience in the Play Games app

Full games that are packaged using Google Play Instant are eligible to be featured prominently on the homepage of the Google Play Games app. These "Instant play" games are full experience games, not trial versions. Players tap on the Instant play button (as shown in Figure 2) to play the full game without installing it first.

Android Implementation Steps

Need to make smaller modular components of app to enable instant functionality.

Instant Apps require the app to be split into a base module and feature modules. The base module holds common resources (UI, core logic), and each feature module contains specific parts of your app (e.g., a payment screen, a product listing page).

To make app modular we can use Dynamic Delivery feature of Android Studio. We can follow this link for the same :- Modularizing Your Android App

Create Instant App Module:-

1. Open your project in Android Studio.

2. Go to File > New > New Module.

3. Choose Instant Dynamic feature. This will generate a module with mini mal functionality—just enough to launch your Instant App.

4. The instant module should reference the relevant feature modules. Add the feature modules you created in the previous step.

Create App Links for Instant Apps

• When you create an intent filter for activities in your app that allow the user to jump straight to a specific screen in your app with a URL link, this is known as a "deep link." Other apps can declare a similar URL intent filter, though, so the system might ask the user which app to open. To create these deep links, read Create Deep Links to App Content.

• When you publish an assetlinks.json file on the website that corresponds to your app's HTTP deep links, you verify that your app is the true owner of those URLs. Thus, you've converted your deep links into Android App Links, which ensure that your app instantly opens when the user clicks such a URL. To create app links, read Verify Android App Links.

• So, Android App Links are simply HTTP deep links that your website is verified to own so that the user doesn't need to choose which app to open. For a more specific description, see differences between deep links and app links.

• In both cases, however, the user must already have your app installed. If the user clicks one of your web site's links and they don't have your app installed (and no other app handles that URL intent), the URL is opened in a web browser. So, creating an Instant App solves this part—it allows users to open your app by simply clicking a URL, even if they don't have your app installed.

• When end users perform a Google search for your app, Google Search displays a URL with the "Instant" badge.

How app links for instant apps are different

• All intent filters used as app links in your instant app must support both HTTP and HTTPS. For example:

          
            < intent-filter >
              < action android:name="android.intent.action.VIEW" />
              < category android:name="android.intent.category.DEFAULT" />
              < category android:name="android.intent.category.BROWSABLE" />
              < data android:scheme="http" android:host="www.example.com" />
              < data android:scheme="https" />
            < /intent-filter >
          
        

• Notice that you don't need to include the host in the second < data> element because, within each < intent-filter> element, all combinations of each < data> attribute are considered valid (so this intent filter does resolve https://www.example.com)

• Only one instant app can be declared for each website domain. (This is unlike when creating app links for your installable app, which allows you to associate a website with multiple apps).

Other reminders when creating app links

• All HTTP URL intent filters in your instant app should be included in your installable app. This is important because once the user installs your full app, tapping a URL should always open the installed app, not the instant app.

• You must set autoVerify="true" in at least one intent filter in both the instant and the installable app. (See how to associate a website with multiple app.)

• You must publish one assetlinks.json for each domain and subdomain supported by your app links, using the HTTPS protocol. (See how to associate a website with multiple app.)

• The assetlinks.json file must be valid JSON, be served without redirects, and be accessible to bots (your robots.txt must allow crawling /.well-known/assetlinks.json).

• Use of wildcards in your intent filter's host attribute is not recommended. (See how to associate a website with multiple app.)

• Custom host/scheme URLs should be declared with separate intent filters.

• • Ensure that your app link URLs account for your top search results for your key terms.

iOS Implementation Steps: A Quick Guide

1. Add an App Clip Target

• Open your app’s project in Xcode.
• Navigate to File > New > Target.
• Choose App Clip as the target type.
• Xcode will generate a new App Clip target alongside your main app target.
• Make sure the App Clip contains only the essential functionality, as it needs to be under 15 MB.

Tutorial: Setting Up App Clips in Xcode

Follow the official guide to create and configure your App Clip target in Xcode.

2. Limit Dependencies

• Ensure the App Clip remains lightweight and under 15 MB.
• Optimize assets like images, videos, and other media by compressing them.
• Avoid including unnecessary libraries or frameworks that aren't used in the App Clip.
• Use Swift Package Manager or CocoaPods to include only the necessary dependencies.

3. Design App Clip UI

• Design a minimalistic user interface in SwiftUI or UIKit.
• Focus on the specific task that your App Clip should accomplish (e.g., making a purchase, booking a service).
• Use App Clip Cards to show a prompt that users can tap to install the full app after using the App Clip.

Tutorial: Designing your App Clip

Apple’s guide to designing a user-friendly App Clip, optimizing for speed and simplicity.

4. Setup Associated Domains

• In the Apple Developer Portal, enable the Associated Domains capability for both your full app and App Clip.
• Create an apple-app-site-association file for your domain, similar to Android's assetlinks.json.
• Place the file in the root of your web server.

Tutorial: Setting up Associated Domains

5. Register Invocation Methods

• Set up App Clip Codes (custom NFC tags and QR codes) for your app clip.
• Use Universal Links to trigger your App Clip via URLs.
• You can also link to your App Clip from Apple Maps, Siri, or iMessages.

Tutorial: Invoking Your App Clip

Detailed tutorial on how to trigger App Clips via various methods like QR codes and NFC tags.