Session Replay

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

Updating to latest SDK version

Section titled 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.

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 React Native Privacy sections.

Enable Session Replay on your device

Section titled 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 replay collection on your device for testing and debugging purposes. This option can be enabled from the in-app features settings:

  1. Enable in-app features
  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

How do I know if Session Replay is enabled?

Section titled 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

The replay 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.

It is required to send us 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.

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 component.

Although the implementation is done once for both iOS and Android on React Native, the visual appearance of the masking itself will be different for each platform:

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

Section titled Original VS Replay fully masked

All components are masked by default. The Bridge provides a simple API to change the default masking state:

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

Masking/Un-masking by instances

Section titled Masking/Un-masking by instances

Use <CSMask isMasking={boolean}> component to mask or unmask one or multiple specific children view components. By default isMasking props is true, so it’s optional to explicitly write it.

In this example below, all children views inside <CSMask> will follow the rule of the closest parent props isMasking.

// Masks or Unmasks all its children views
<CSMask isMasking={true | false}>
<View>
<Text style={styles.title}>Buy my amazing merch!</Text>
<Text>
Hurry up! This offer won't be available tomorrow. Only
$99.98 to get hands on a wonderful brandnew life changing
item
</Text>
</View>
</CSMask>

You have the ability to create nested structures with <CSMask> components, which means you can include a <CSMask> component within another <CSMask> component. For example if you want to unmask components inside a parent masked view layout.

Implementation recommendations

Section titled Implementation recommendations

Keeping track of what is masked

Section titled Keeping track of what is masked

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

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.

Section titled Get current Session Replay Link

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

const link = await Contentsquare.getCurrentSessionReplayLink();

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.

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.

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

During the early access phase, the percentage of 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

Refer to Compatibility

The 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).

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.

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 your project’s configuration.

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 has been able to send the data.

The maximum request size is 1Mbyte.

Android

Requests are sent:

iOS

Requests are sent:

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.

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:

ConditionValue
Device modelPixel 5
Android version33 (Android 13)
Quality levelHigh
Default Masking StateDisabled
PropertyValue
Total % on main thread (CPU Profiling)< 10 %
Memory overhead10 MB
Session Replay data transmitted over network during 1 minute of use:
- with “High quality” level< 300 kB
- with “Medium quality” level< 200 kB
- with “Low quality” level< 100 kB
Additional info on performance test procedure
Section titled 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 the Session Replay activated. Session Replay requires to perform tasks on the main thread (screen capture and view hierarchy inspection).

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.

Most operations related to Session Replay 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 the Session Replay 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 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.

The following performance results were obtained under the following conditions:

ConditionValue
Device modeliPhone 7
iOS version15.7.8
Test App built using Xcode version14.3.1
Test App built with Swift version5.8
Quality levelHigh
Default Masking StateDisabled

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.

PropertyValue
Max CPU overhead<10%
Max RAM usage<5MB
Session Replay data transmitted over network during 1 minute of use
- with “High quality” level<2Mbytes
- with “Medium quality” level<1Mbytes
- with “Low quality” level<900Kbytes
  • Different quality levels are not available for the moment.
  • Getting the replay link programmatically is not available for the moment.
  • There is a known layout glitch of animations on iOS.
  • There is a discrepancy of the default iOS Font between devices and Session Replay.

All limitations will be fixed on future releases. Refer to the changelog.

Requests are not sent from an Android emulator / iOS simulator

Section titled Requests are not sent from an Android emulator / iOS simulator

If you struggle to watch a replay collection 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:

Very long session on an Android emulator / iOS simulator

Section titled 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.