What is a HAR file and How it is structured

The information about network requests made by the client and server inside the browser is contained in HAR files, also known as HTTP Archive files. These files are formatted in JSON and are mostly used to analyze issues with request and response performance, sluggish API calls, page rendering, or load times.

HAR file details

HAR file format uses a JSON structure and to visualize its contents you can use tools like HAR Viewer or network viewer.

To analyze the performance of a site, you can export the HAR file by following the steps below.

1. First, open the Network tab in Chrome DevTools.

   a] Open Google Chrome Browser

   b] At the top right corner click on Three Dots > More Tools > Developer Tools > Network Tab

2. After opening the network tab, you can see the small export icon (⬇️) which can be used to export the HAR file.

3. To capture site loading content, make sure network log recording is enabled, and then refresh or reload the page whose network requests you want to analyze. The red circle icon (🔴) indicates that network log recording is on.

4. That’s all — now you can export the HAR file to analyze it.

How to export HAR with sensitive data

Chrome sanitizes HAR exports by default, so cookies, Set-Cookie, and Authorization headers may be excluded. If you need the full session data for debugging, enable the sensitive data option before exporting.

1. Open Chrome DevTools and go to Settings.

2. In Preferences, scroll to the Network section.

3. Enable Allow to generate HAR with sensitive data.

4. Go back to the Network tab and reload the page so the requests are captured again.

5. Export the HAR file using the download/export icon. Chrome will now include the sensitive request data in the HAR export.

Warning: Only export HAR files with sensitive data when it is necessary, and share them carefully because they can contain cookies, auth tokens, and private user information.