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Browser SDK

Sematext Browser SDK is an open-source framework used to ship web application metrics related to user interaction. Using Browser SDK allows gathering metrics related to:

Sematext Experience Overview


You can find the information about the development and script architecture in the Browser SDK Github project:

Supported Commands

The following commands are currently supported by the Experience script:

  • config - Configures the script. It requires the token and receiverUrl configuration parameters. You can also provide the ignoreBotData Boolean parameter to ignore metrics coming from bots.
  • identify - Identifies the user. Requires the name and the identifier keys to be present, which are used to identify a user.
  • routeChange - Informs the metrics gathering script about a route change. It accepts a single parameter that should take the value of the new route.
  • startTransaction - Informs the metrics gathering script about transaction start. It accepts two parameters. The first is the transaction name. The second parameter is optional custom tags.
  • endTransaction - Informs the metrics gathering script about transaction end. It accepts a single parameter that should take the value of the name of the transaction that we want to end.
  • pageLoad - Provides metrics related to page load.
  • ajax - Provides metrics related to HTTP requests.
  • longTask - Provides metrics related to long tasks.
  • elementTiming - Provides metrics related to element timing.
  • vitalMetric - Provides metrics related to web vitals.

Global Constants

The Experience script uses global constants defined in the constants.js file. The file contains the following constants:

  • GLOBAL_KEY - The global key under which the script is available.
  • DEBUG_PARAM_KEY - When set to true turns on the debug level logging.
  • SESSION_COOKIE - Name of the cookie related to a user session.
  • USER_COOKIE - Name of the cookie related to the user.
  • SESSION_KEEP_ALIVE_MINUTES - The maximum time for the session to be kept alive.
  • PAGELOAD_HARD_TIMEOUT - Timeout after which the events are no longer considered to be part of the hard page load.
  • PAGELOAD_SOFT_TIMEOUT - Timeout after which the events are no longer considered to be part of the soft page load.
  • BOT_USER_AGENT - Regex used for bots identification.


Installation of the Experience script contains the following steps:

Adding the Loader Script

To add the loader script responsible for loading the main Experience script you need to add the RUM loader snippet generated via the yarn generate-snippet command to the header of the page before the closing </head> tag:

<script type="text/javascript">

The /experience.js should be pointing to the location of the built Experience script and the strum is the key under which the script will be available.

Configuring the Experience Script

To configure the script the config command needs to be sent providing the URL of the receiver which accepts the data and the token, which identifies the Sematext Experience App. For example:

strum('config', { token: '8763d12d-1j3t-932v-b498-544290z98k43', receiverUrl: '' });

Integrating the Experience Script

For some web technologies, especially those used in single-page applications additional integration may be needed. Have a look at the Sematext Experience Integrations to learn more.

Customizing Browser SDK

You can use the Sematext Browser SDK to implement more complex monitoring solutions and collect the exact metrics you want from real users in real browsers in real time. See Getting Started with Sematext Browser SDK for Front-end Performance Monitoring.


Pull requests for bug fixes, improvements and new features for the Browser SDK are more than welcome. You can open a pull request on the project Github page. When opening a new pull request please take the time to briefly describe the changes. Make sure that the newly introduced code passes the lint and flow checks along with the integration tests.

Learn More

Learn more about Sematext Experience.