Mobile SDK Session Replay

Introduction

Session Replay is a feature available as an add-on to CS Apps Analytics. For more information, reach out to your Contentsquare contact.

Prerequisites

Screen tracking implemented

As session data collection will start at the 1st screenview event, it is required to have screen tracking implemented. Make sure to follow the Android Track screens or iOS Track screens sections.

Updating to latest SDK version

In order to enable Session Replay in your app and get the most stable version, it is required to upgrade the SDK to its latest version.

Reminder about User consent

If you are in the process of implementing the SDK for the 1st time (or choose to take this update as an opportunity to review your Privacy related implementation), make sure to follow the Android Privacy or iOS Privacy sections.

Testing and Debugging

Enable Session Replay on your device

Since not all sessions are collected (depending on the percentage set in Contentsquare back-office), we have implemented an option to force data collection for Session Replay on your device for testing and debugging purpose. This option can be enabled from the in-app features settings:

1. Enable in-app features: iOS | Android
2. Open in-app features settings with a long press on the snapshot button
3. In the "Session replay settings" section, enable session Replay
4. Kill the app
5. Start app, a new session is starting with Session Replay enabled

[tab] Android

How do I know if Session Replay is enabled?

There are 2 places where you can check if Session Replay is enabled:

In the logs: The log I/CSLIB|SessionReplay: Starting Session Replay. will confirm that Session Replay is enabled.

In in-app features settings: Below the "Enable "will start at next app start" (see below Access the replay), you will either see:

• No replay link available which means Session Replay is not running for the current session
• Get Replay link which means Session Replay is running for the current session

[tab] iOS

How do I know if Session Replay is enabled?

There are 2 places where you can check if Session Replay is enabled:

In the logs: The log Session Recording is starting will confirm that Session Replay is enabled.

In in-app features settings: Below the "Enable "will start at next app start" (see below Access the replay), you will either see:

• No replay link available which means Session Replay is not running for the current session
• Get Replay link which means Session Replay is running for the current session

Access the Replay

[tab] Android

Since 4.6.0, the Session can be accessed by tapping on Get replay link button from the in-app features settings:

The replay will be available within 5 minutes. Only the "ended screen views" are processed (we know a screenview is ended when we start receiving data for the next screenview). This means that you will be able to replay your session up to the previous screenview if the session is still running.

[tab] iOS

The session can be accessed by tapping on Get replay link button from the in-app features settings:

The replay will be available within 5 minutes. Only the "ended screen views" are processed (we know a screenview is ended when we start receiving data for the next screenview). This means that you will be able to replay your session up to the previous screenview if the session is still running.

Provide custom fonts (iOS only)

On iOS, since text is collected as is for UIKit elements, it is required to get the custom fonts you use in your app so we can use them to render text properly.

Provide the fonts requested by your Implementation Manager in one of the following formats: otf, ttf, woff or woff2.

Personal Data Masking

The Session Replay feature collects every interaction of your users with your app. In order to respect the user’s right to privacy, the Contentsquare SDK :

• Masks everything by default
• Allows you to control which part of the user interface is collected via our masking and un-masking APIs.

Masking mechanisms

Masking mechanisms are different on iOS and Android:

[tab] Android

Every single UI element is converted into a highly pixelized image to reach a very low resolution. Text and images will appear very blurry so that the content cannot be identified.

Original VS Replay fully masked

[tab] iOS

On iOS, masking depends on the type of element:

• UIKit.UIImage and SwiftUI.Image: image isn't collected, a placeholder is sent instead of the content; the "IMG" placeholder will be displayed in the frame of the element.
• UIKit.UILabel and UIKit.UITextView: text is replaced by "la" repeated as many times as needed to equal the original character count. White characters are preserved. For instance the lazy fox is collected as lal lala ala. All other visual properties are collected (text color, background color, alignment, etc.).
• UIKit.UITextField: same as UIKit.UILabel or UIKit.UITextView unless isSecureTextEntry is set to true. In this case all characters, including whitespaces are replaced with "•".
• SwiftUI.Text: element is replaced by a black rectangle.
• For all other types: no specific data is collected but all visual properties are collected: size, background color, corner radius, etc.

If you think a specific element can reveal personal data from one of these properties you have to mask it using one of the method presented below. A good way to check how a view is rendered in the Session Replay is to navigate to the desired view with the CS SDK running then use the quick replay link.

Original VS Replay fully masked

Default masking

[tab] Android

All Android View elements and their subclasses are fully masked by default. The SDK provides a simple API to change the default masking state:

/**
* Set the default masking of all the views.
* @param masked true mask all views by default.
*               false unmask all views by default.
*               The default value is true.
*/
setDefaultMasking(boolean masked)

[tab] iOS

All iOS views and subclasses of UIView are fully masked by default. The SDK provides a simple API to change the default masking state:

/// Change the masking state of all types of views.
/// - Parameter mask: true restores the default masking state.
///                   false unmasks every types of views.
static func setDefaultMasking(_ mask: Bool)

Masking/Un-masking by instances

[tab] Android

Use mask(View view) and unmask(View view) methods to mask or unmask a specific view instance.

/**
* Masks a specific {@link View} during data collection for session replay.
*
* @param view an instance of {@link View} to be masked.
*/
public static void mask(@NonNull View view)

/**
* Unmasks a specific {@link View} during data collection for session replay.
*
* @param view an instance of {@link View} to be unmasked.
*/
public static void unMask(@NonNull View view)

Following the previous example, we have the views hierarchy in which all instances of TextView type are unmasked with the default masking state of all the views are masked by default.

In this example you may want to mask a specific text view TextView1, you can simply call mask(textView1) then this instance of TextView1 will be masked. As you can see in this example the view instance rule overrides the type rule and the default rule.

[tab] iOS (UIKit)

Use mask(view:) and unmask(view:) methods to deal with a specific instance. Masking is applied recursively to all subviews unless specified otherwise (cf. Masking and Unmasking behaviors on a parent view).

Following the previous example on un-masking UIButtons: you are in default masking, the UIButton are unmasked but a screen shows a button, myButton, that contains sensitive information. You will be able to mask it with mask(view: myButton).

[tab] iOS (SwiftUI)

You can mask or unmask a SwiftUI View instance by using the following view modifier. Masking is applied recursively to all subviews unless specified otherwise (cf. Masking and Unmasking behaviors on a parent view).

@ViewBuilder
func csMasking(_ shouldMask: Bool) -> some View

Masking/Un-masking by type

The Contentsquare SDK allows masking elements by type for convenience but it isn't the recommended masking mechanism because it will impact all screens of your application. For instance, it can be useful in the case where you have a specific class for presenting user information or for displaying the user profile picture to make sure it always stays mask.

[tab] Android

Use mask(Class type) and unmask(Class type) methods to mask or unmask a specific type.

/*
* Masks all instances of a specific {@link Class}
* and subclass of a view during data collection for session replay.
*
* @param type {@link Class} to be masked.
*/
public static void mask(@NonNull Class<?> type)

/**
* Unmasks all instances of a specific {@link Class}
* and subclass of a view during data collection for session replay.
*
* @param type {@link Class} to be unmasked.
*/
public static void unMask(@NonNull Class<?> type)

For example, given the views hierarchy:

The default masking state of all the views is masked by default and for example, you may want to unmask all TextView types, you can simply call unMask(TextView.class) then all instances of TextView type will be unmasked. In this example, the button is also impacted by the unmask API because the button is also a TextView type (a subclass of TextView). You can also notice that the EditText is also a TextView type but it is not impacted by unMask(TextView.class) call because the EditText type is masked by default see Masking rules priority.

[tab] iOS (UIKit)

Use mask(viewsOfType:) and unmask(viewsOfType:) methods if you want to handle a specific type (wether being a system element or a custom element).

Example: un-masking UIButtons If you are in default masking but you don’t want any button to be masked, you will only need to call unmask(viewsOfType: UIButton.self): to specify that all instances of UIButton and its subclasses should not be masked.

[tab] iOS (SwiftUI)

Masking/unmasking by type can be achieved using 1 or more of the 3 following methods.

/// Masks or unmasks all text elements.
///
/// The text elements are `Text` for SwiftUI and `UILabel` for UIKit 
static func maskTexts(_ mask: Bool)

/// Masks or unmasks all image elements.
///
/// The image elements are `Image` for SwiftUI and `UIImageView` for UIKit.
static func maskImages(_ mask: Bool)

/// Masks or unmasks all text input elements.
///
/// The text input elements are `TextField`, `SecureField`, `TextEditor` for SwiftUI 
/// and `UITextField`, `UITextView` for UIKit.
/// 
static func maskTextInputs(_ mask: Bool)

Masking rules priority

[tab] Android

The SDK determines if a view is masked or unmasked by applying the rules in the following order:

The default masking rule will be overridden by the type rule if there is a specific call to mask(Class type) or unMask(Class type) on a specific type and if there is a call to mask(View view) or unMask(View view) on a specific view instance, the view instance rule will be applied instead of the type rule and the default rule.

[tab] iOS

The SDK determines if a view is masked or not by applying the above rules in the following order. Once a rule is triggered, the state is set (subsequent rules won't be applied):

Masking and Unmasking behaviors on a parent view

[tab] Android

The masking of the ViewGroup (RelativeLayout, LinearLayout, ConstraintLayout, etc..) is supported. If a parent view is masked all of its children will inherit the masking state from the parent. The children's view masking state can be overridden by using a specific API to mask or unmask by instance or by type.

For example, given the view hierarchy with the default masking state. All the views are masked by default in the initial state and in this case, you may want to unmask all children’s views of the parent view LinearLayout1, you can simply call unMask(linearLayout1) then all children views of the parent view LinearLayout1 will be unmasked. As noticed here the EditText is not impacted from the parent call because the EditText type is masked by default Masking rules priority.

[tab] iOS (UIKit)

Masking is applied recursively to all children unless a specific rule has been applied to 1 of them. In this case the rule will again be applied recursively.

Examples

Let's say we have the following structure:

   (parent view)
   ------------------------
   |    "Parent Label"    |
   |                      |
   | (child view)         |
   | -------------------- |
   | |   "Child Label"  | |
   | |                  | |
   | -------------------- |
   |                      |
   ------------------------

• If no rule is applied: everything is masked including "Parent Label" and "Child Label"
• If parent view is unmasked and no other rule is applied: both "Parent Label" and "Child Label" are unmasked
• If parent view is unmasked and child view is masked: "Parent Label" is unmasked and "Child Label" is masked
• If default masking is set to false and no other rule is applied: "Parent Label" and "Child Label" are unmasked
• If default masking is set to false and parent view is masked: both "Parent Label" and "Child Label" are masked

And so on as explained in the Masking rules priority.

Unmask an instance when its type is masked If you've masked UILabel types specifically or are in default masking, and you call unmask(view: myLabel), all UILabel instances will be masked except myLabel.

Mask an instance when its type is unmasked If you've unmasked UILabel type specifically or are using the default masking, and you call mask(view: myLabel), no UILabel will be masked except myLabel.

Implementation recommendations

Where to perform masking operations

[tab] Android

Masking operation should be performed before the first draw of the view and it should always be called on the UI thread.

At the Activity level, call the masking API methods on the onCreated lifecycle method.

At the Fragment level, call the masking API methods on the onViewCreated lifecycle method.

[tab] iOS (UIKit)

Masking operations should always be performed before the target view is added to the window to avoid any Personal Data leak. For instance, you can set up masking in the didFinishLaunching callback of your app or if you need to change masking behavior while your app is launched, it can be done in loadView, viewDidLoad or viewWillAppear if you use a ViewController.

[tab] iOS (SwiftUI)

Masking operations should be done as early as possible, in the setup of your app for masking by types for instance. For masking by instance, you can do it in the body of your View by calling the modifier csMasking.

Keeping track of what is masked

The SDK doesn't provide a list of what is currently masked, if you need to keep track, you probably will have to write your specific wrapper.

Masking operations performance impact

[tab] Android

Repeating the same operation has little to no impact, e.g you can call unmask(View view) multiple times without impacting the SDK or your app performances.

[tab] iOS

Repeating the same operation has little to no impact, e.g you can call unmask(viewsOfType: UIButton.self) multiple times without impacting the SDK or your app performances.

Integrations

Contentsquare provides the ability to retrieve the link to the session replay to be attached to other vendors such as Voice of customers tools, Crash reporting tools.

Get current Session Replay Link

[tab] Android

Use the following code to retrieve the current session replay link:

val replayLink = Contentsquare.currentSessionReplayLink()

When called, the SDK will log:

I/CSLIB: SessionReplay link: https://app.contentsquare.com/quick-playback/index.html?pid={projectId}&uu={userId}&sn={sessionNumber}&recordingType=cs

If you have a Contentsquare account, you can use this link to directly watch your current session replay on the Contentsquare Platform.

The replay will be available within 5 minutes. Only the "ended screen views" are processed (we know a screenview is ended when we start receiving data for the next screenview). This means that you will be able to replay the session up to the previous screenview if the session is still running.

[tab] iOS

Use the following code to retrieve the current session replay link:

let replayLink: URL? = Contentsquare.currentSessionReplayLink

When called, the SDK will log:

CSLIB ℹ️ Info: SessionReplay link: https://app.contentsquare.com/quick-playback/index.html?pid={projectId}&uu={userId}&sn={sessionNumber}&recordingType=cs

If you have a Contentsquare account, you can use this link to directly watch your current session replay on the Contentsquare Platform.

The replay will be available within 5 minutes. Only the "ended screen views" are processed (we know a screenview is ended when we start receiving data for the next screenview). This means that you will be able to replay the session up to the previous screenview if the session is still running.

How Session Replay works

Initialization

Sessions can be collected for Session Replay if the Session Replay feature has been enabled for your project and the session matches the collection criteria.

The following conditions will have an impact on which sessions will be collected:

• User consent: The users have given their consent (if required)
• Collection rate: The session is being drawn for collection (see Collection rate below)
• Compatibility: The OS version is supported.
• App version: The app version is not part of the block list (see App version block list below)

Note that, when Session Replay is turned off, no content specific to Session Replay is collected whatsoever. Also note that the standard Contentsquare analytics tracking remain unaffected by this.

Collection rate

Data collection for Session Replay is based on a percentage of the total sessions. By default data collection for Session Replay is disabled.

During the early access phase, the percentage or collected sessions will be set to 1% at the beginning. It will then be adjusted according to:

• The traffic on your app
• The volume of collected sessions set in the contract

Compatibility

Refer to the respective compatibility sections: Android and iOS.

App version block list

Contentsquare team can add versions of your app in the block list to make sure Session Replay does not start on these versions. This can be useful when a problem is discovered on a specific version of your app, such as a Personal Data for which the masking was forgotten. This allows to keep Session Replay working on the other app versions (especially the new ones with the fix).

Data collection

The SDK monitors the application lifecycle events and the view hierarchy, and generates session replay data from the behavior of the app, the content of the screen and the interaction of the user. These events are then locally stored, and eventually sent to our servers in batches. We then aggregate that data to create usable visual information into our Web Application, which you use to gather insights.

Quality levels

Session Replay has three quality levels available: High, Medium, Low. Quality level is defined by the frame rate and the image quality. The quality level is defined independently for Wi-Fi and Cellular Network. The default level for both is Medium. For more information on network data consumption see: Performance Impact section.

Quality level examples

Android

Select the image to open the it in full size and GIF format.

iOS

Select the image to open the it in full size and GIF format.

Network and Storage

By default, Session Replay data can be sent over cellular network. If the particular context of your app and/or users requires a very limited impact on cellular data consumption, sending data over cellular network can be completely disabled. Once disabled, data will be sent when the device is using Wi-Fi.

Reach out to your Contentsquare contact that will make the adjustment in the project configuration.

Storage

Before being sent, data is stored in local files on disk up to 30MB on iOS and 20MB on Android. If the limit is reached, Session Replay is stopped. It will restart at the next app launch once the SDK is able to send the data.

Requests

The maximum request size is 1Mbyte.

[tab] Android

Requests are sent:

• Every 5 seconds
• On screen change
• When Replay Link API is called

[tab] iOS

Requests are sent:

• Every 10 seconds
• At app hide
• When Replay Link API is called

Performance impact

[tab] Android

Performance impact mitigation

Most operations related to Session Replay are performed on dedicated background threads, for a minimal impact on the main thread. If CPU usage is too high for background tasks, some expensive calculations will be discarded. To make sure of this, we run performance tests on testing applications, along with the Android profiler.

If too much time is spent on the main thread, the quality level will decrease automatically: from high to medium to low to a complete stop if required. Once conditions are back to normal, quality level will be changed back to the default value set in the configuration.

We defined our network strategy to have the lesser impact on CPU, memory and data consumption of the users devices. We measure these impacts, using the Android profiler and dedicated logging system, for each release of our SDK.

You can reduce the quality level if you want to favor performance impact over quality.

Performance test results

We always strive to be non-intrusive, and transparent to the developers of the client app. We apply this rule on the performance as well. These are the technical specifics we can share on performance, if you have any questions feel free to reach out to us.

The performances results were obtained under the following conditions:

Additional info on performance test procedure

CPU Usage Test We are profiling our Demo app with and without the SDK dependency by following the same use case. We are measuring the CPU peak for both versions of the app and we are computing the difference.

RAM Usage Test We are profiling our Demo app with and without the SDK dependency by following the same use case. We are measuring the RAM usage peak for both versions of the app and we are computing the difference.

Memory Leak Test We are profiling our demo app and we are using the ADB Monkey tool to create random user input events. During this time we are monitoring the RAM behavior for any anomaly. We are using the Memory Profiler to identify leaks.

Data consumption We replay a predefined, repeatable and automated user scenario on our demo app and all data sent is measured in kB/min.

JankStats If you use the alpha library from Google to monitor the jank frames and you already have some jank frames in your application (main thread overwhelmed), you can expect an increase of 1% or 2% with data collection for Session Replay activated. Data collection for Session Replay requires to perform tasks on the main thread (screen capture and view hierarchy inspection).

[tab] iOS

We always strive to be non-intrusive, and transparent to the developers of the client app. We apply this rule on the performance as well. These are the technical specifics we can share on performance, if you have any questions feel free to reach out to us.

Performance impact mitigation

Most operations related to Session Replay data collection are performed on background threads, for the impact on the main thread to be minimal. To make sure of this, we run performance tests on testing applications, using XCTMetric and Hitch Time Ratio measures.

We also set up mechanisms that stop Session Replay data collection if we detect the feature is using too much memory.

We defined our network strategy to have the lesser impact on CPU and battery of the users devices. We measure these impacts, using Apple Dev Tools, for each release of our SDK.

Session Replay data collection will also stop if we use up to 30Mbytes of local storage.

You can reduce the quality level if you want to favor performance impact over quality.

Performance test results

The following performance results were obtained under the following conditions:

We conducted the tests using a default Master-Detail app built using AdHoc distribution with no app thinning and with Swift symbols stripped. In the app, the SDK was making calls to the Public APIs, running and collecting data in its default state.

Known limitations

[tab] Android

WebViews

WebViews can contain potential Personal Data and are therefore masked by default. You can unmask a WebView, that will then be captured as an image in the Session Replay. However, you won't be able to mask or unmask specific elements within the WebView.

Maps

You can mask or unmask a Map, that will then be captured as an image in the Session Replay. However, you won't be able to mask or unmask specific elements within the Map.

Jetpack Compose

Jetpack Compose is currently not fully supported. For now, Compose elements are captured as images in the Session Replay. You can mask or unmask a entire component (AndroidComposeView), but you won't be able to specify the masking rules for its subviews (the Compose components inside this AndroidComposeView).

Contentsquare.mask(ComposeView::class.java)

Views on top of the application views

If your application uses some library that display views on top of your application views hierarchy, like a MaterialShowcaseView, these views may not be visible in the Session Replay.

Transparent Views and masking

An unmasked transparent view on top of other masked views will act as an unmask layer.

[tab] iOS

Maps and WebViews

Maps and WebViews can contain potential Personal Data and are therefore replaced by a placeholder with no ability to un-mask them currently.

NSAttributedString handling

The exported HTML doesn’t support the expansion, obliqueness, paragraphStyle and textEffect attributes.

Multiple windows

Multi-window is not supported.

System elements

System elements like UIImagePickerController, SKStoreReviewController are not collected.

Troubleshooting

Requests are not sent from an Android emulator / iOS simulator

If you struggle to watch a replay created on an emulator/simulator, it may be due to some network constraints applied on your computer (VPN, company network restrictions, etc.). Check your configuration and/or use a real device.

See following sections for more information about our endpoints and requests:

• Android - Requests are failing
• iOS - Requests are failing

Very long session on an Android emulator / iOS simulator

It is important to remember that an app kill does not end a session. See Session definition for more information. If you leave the simulator/emulator running with the app in foreground, the session will not end, even if you are inactive. To better reflect actual end user behavior and avoid unusually long sessions (last hours), put the app in background or kill it.

Unmasking with CS InApp features is broken

When activating the toggle in CS InApp to unmask the elements in the Session Replay, it can sometimes give a strange result with some elements still masked, it's especially true for SwiftUI. This is due to the fact that unmasking with InApp features acts differently that when done in the code by the app developer. To ensure a session is fully unmasked as it would be if it was done in the code of the app, follow these steps:

• Toggle the "Unmask ..." switch
• Navigate to a different screen
• Go back to the previous screen
• Put the app in background
• Wait for the session timeout
• Re-open the app From this point on, you will have a fully unmasked session.