Skip to main content

Network Traffic Capture

Network Traffic Capture is a functionality that gives you the ability to record network traffic for HTTP/HTTPS requests during Android and iOS/iPadOS mobile app tests on real devices. This provides granular insight into your app’s behavior, facilitates debugging, and helps you determine which development team is responsible for application failure.

With this feature, traffic is recorded on our side and exposes the HAR file through your test’s endpoint, producing HTTP traffic information to help you troubleshoot.

What You'll Need

  • A Sauce Labs account (Log in or sign up for a free trial license)
  • A native Android, iOS, or iPadOS mobile app that makes HTTP/HTTPS requests. We currently support the following:
    • Android 6.0 and higher
    • For Swift: iOS 11.0 and higher
    • For Objective-C: iOS (all)

Using Network Traffic Capture

To enable network traffic capturing in your tests:

  1. On Sauce Labs, click Live > Mobile App.

  2. Upload your mobile app to Sauce Labs through our UI or our REST API.

  3. After you’ve uploaded your app, return to the Live > Mobile App page, hover your mouse over your app, then select Settings.
    Mobile app settings navigation

  4. Under Default Settings, toggle Instrumentation and Network Capture to enable the feature.
    Mobile app settings navigation

  5. For Automated Testing only: add the networkCapture capability to your test script. Click the link below corresponding to your framework:

Now you can start your live or automated testing session. Your network logs will be captured and displayed in the test results page.

Accessing HAR Files

To download HAR files from Sauce Labs:

  1. Navigate to Test Results.
  2. Select the applicable test.
  3. Click the Network tab in the bottom to preview network calls.
  4. Click the Logs tab on the right panel and select network.har from the dropdown menu to download the report.

You can also download a HAR file programmatically using the following API request:

curl --compressed \

Viewing HAR Files

You'll need a HAR viewer to read HAR files. Sauce Labs provides a React Network Viewer HAR viewer for your convenience. For step-by-step usage instructions, see our Visualize HAR Files with the New React Network Viewer blog article.

Alternatively, some other commonly used HAR viewers include:

HAR Files

HTTP Archive Format (HAR) files collect all network requests and responses made and received by the browser during testing. HAR files offer useful debugging information, such as:

  • Identifying browser requests that time out
  • Pinpointing requests slowing down the loading process
  • Locating faulty API calls


Not Supported
  • Android Emulators
  • iOS Simulators
  • Hybrid Applications (React Native, Cordova, Flutter)
  • Android Chrome Browser
  • iOS Safari Browser


Our network capture code depends on the fact that these classes are not obfuscated:


  • okhttp3.Interceptor
  • okhttp3.OkHttpClient
  • okhttp3.Request
  • okhttp3.Response
  • okhttp3.ResponseBody
  • okio.Buffer




More Information