What are UXWizz callbacks?

The UXWizz callbacks or hooks are a way to tap into the client-side UXWizz tracking functionality and listen to specific events. This is useful, for example, if you want to read or forward some UXWizz tracking data to another service.

Available callbacks

  • UST.onLoaded()

    • Called as soon as the ust.min.js finishes loading.

  • UST.onTrackingStarted() : false | undefined

    • Called when all tracking checks passed, meaning that a new session will be created.

    • This is called before the session was created.

    • If you want to stop creating this session, return false from this function.

  • UST.onSessionCreated(clientID: number)

    • Called when the UXWizz server create a new session for this client

    • clientID: The integer number ID of the session.

    • This is called only once per visit for each visitor.

  • UST.onPageViewCreated(clientID: number, clientPageID: number)

    • Called when a new page has loaded and the server responded with the pageview ID.

    • clientID: The integer ID of the session.

    • clientPageID: The integer ID of the pageview.

    • This callback is also called once immediately after onSessionCreated (first pageview).

  • UST.onDataSent(data: string[])

    • Called whenever tracking data (session recording/heatmap data) is sent to the server.

    • data: An array of data strings sent to the server. Each data string is in the format c=XXX where c is the data type and XXX is the data value. The data type can be:

  • UST.onTagAdded(tag: string)

    • Called when UST.addTag() was called and the server responded.

    • tag: The string that has just been added as a tag to the current user.

  • UST.onEventAdded(eventData: Event)

    • Added in version 3.5.0

    • Called when UST.addEvent() was called and the server responded.

    • eventData: The original eventData passed, also containing clientID and clientPageID

  • UST.onGDPRAccepted()

    • Called when the user accepted the UXWizz tracking consent pop-up.

  • UST.onGDPRDeclined()

    • Called when the user declined the UXWizz tracking consent pop-up.

Usage example

Make sure write the callbacks declarations after the tracking file is included.

Example: Multiple UXWizz callbacks

// <head>
// After ust.min.js include snippet
// ...
// <script>

// Example: User will be recorded
UST.onTrackingStarted = function() {
    console.log('Creating session...!');
// Example: New session has been created with an unique clientID
UST.onSessionCreated = function(clientID) {
     console.log('New session created for client', clientID);

// Example: whenever a tag is added, add the same tag + current pageID
UST.onTagAdded = function(tag) {
    if (tag === 'AddToCart' || tag === 'Converted') {
         UST.addTag(tag + ';' + sessionStorage.clientPageID);

// <script>
// </head>

Example: Dynamically disable tracking the current visitor

// Example: Permanently disable tracking a visitor once they reached checkout
UST.onTrackingStarted = function() {
    if (window.location.path === '/checkout-complete') {
        // Starting with the next page-load disable tracking this user (permanently)
        // Return `false` to stop tracking this first pageview too
        return false;

Example: Track the current user but disable session recording

UST.onTrackingStarted = function() {
     // Disable session recording for specific IPs
     // Note: `ust_myIP` is globally populated ONLY if you have set 
     // some excluded IPs in the tracking settings
     if (['123.456.12.13', ''].indexOf(ust_myIP) !== -1) {
         UST.settings.enableSessionRecordings =  false; // Disable sending rec data
         UST.fullRec = false; // Disable attaching the full recorder
         UST.nativeSessionRecording = false; // Disable attaching the native recorder
     console.log('Creating pageview...!');

After the session has been created (onSessionCreated), you can always read the current userTrack clientID and clientPageID from sessionStorage:



sessionStorage.getItem('token') token - Another unique identifier per session (similar to clientID). This is useful as it's not incremental.


Positions string (compressed format):

// For example:

Recording string (compressed format)

// This is more complex, looking at the data send or in the ust_records
// Should give you some idea of the format
// Some event names and their shorthand character:
enum PlaybackEventType {
    CLICK = 'c',
    SCROLL = 's',
    MOVEMENT = 'm',
    INACTIVITY = 'i',
    BLUR_INPUT = 'b',
    WINDOW_RESIZE = 'r',

// For example

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