Set Up Session Replay

Session Replay helps you get to the root cause of an error or latency issue faster by providing you with a reproduction of what was happening in the user's device before, during, and after the issue. You can rewind and replay your application's state and see key user interactions, like taps, swipes, network requests, and console entries, in a single UI.

By default, our Session Replay SDK masks all text content, images, and user input, giving you heightened confidence that no sensitive data will leave the device. To learn more, see product docs.

Pre-requisites

Make sure your Sentry Flutter SDK version is at least 8.9.0, which is required for Session Replay. You can update your pubspec.yaml to the matching version:

dependencies:
  sentry_flutter: ^8.9.0

Setup

To set up the integration, add the following to your Sentry initialization:

await SentryFlutter.init(
  (options) {
    ...
    options.experimental.replay.sessionSampleRate = 1.0;
    options.experimental.replay.onErrorSampleRate = 1.0;
  },
  appRunner: () => runApp(MyApp()),
);

Verify

While you're testing, we recommend that you set sessionSampleRate to 1.0. This ensures that every user session will be sent to Sentry.

Once testing is complete, we recommend lowering this value in production. We still recommend keeping onErrorSampleRate set to 1.0.

Sampling

Sampling allows you to control how much of your website's traffic will result in a Session Replay. There are two sample rates you can adjust to get the replays relevant to you:

1. sessionSampleRate - The sample rate for replays that begin recording immediately and last the entirety of a user's session.
2. onErrorSampleRate - The sample rate for replays that are recorded when an error happens. This type of replay will record up to a minute of events prior to the error and continue recording until the session ends.

Sampling starts as soon as a session begins. The sessionSampleRate is then evaluated. If the session is sampled, replay recording will start immediately. If not, onErrorSampleRate will be evaluated. If the session is sampled at this point, the replay will be buffered and will only be uploaded to Sentry if an error occurs.

Privacy

The SDK is recording and aggressively redacting (masking) all Text, EditableText, and Image widgets. Masking in the Sentry Flutter SDK is based on Widget types, e.g. Image, not the string representation of the type (i.e. we check whether a widgetInstance should be masked by checking if (widgetInstance is Image) instead of if (widgetInstance.runtimeType == 'Image')). This means we can ensure masking works regardless of obfuscation in release builds and also works for subclasses. However, it also means we can only automatically mask widgets that are part of the Flutter SDK itself.

You can tune this and add custom masking rules to fit your needs by adjusting the configuration in options.experimental.replay. For example, you can explicitly mask or unmask widgets by type, or you can even have a callback to decide whether a specific widget instance should be masked:

  options.experimental.replay.mask<IconButton>();
  options.experimental.replay.unmask<Image>();
  options.experimental.replay.maskCallback<Text>(
      (Element element, Text widget) =>
          (widget.data?.contains('secret') ?? false)
              ? SentryMaskingDecision.mask
              : SentryMaskingDecision.continueProcessing);

You can find more details in the documentation for each method.

To disable redaction altogether (not to be used on applications with sensitive data):

  options.experimental.replay.maskAllText = false;
  options.experimental.replay.maskAllImages = false;

Error Linking

Errors that happen while a replay is running will be linked to the replay, making it possible to jump between related issues and replays. However, it's possible that in some cases the error count reported on the Replays Details page won't match the actual errors that have been captured. That's because errors can be lost, and while this is uncommon, there are a few reasons why it could happen:

• The replay was rate-limited and couldn't be accepted.
• The replay was deleted by a member of your org.
• There were network errors and the replay wasn't saved.