Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The read-only interactionId property returns an ID that uniquely identifies a user interaction which triggered a series of associated events.


When a user interacts with a web page, a user interaction (for example a click) usually triggers a sequence of events, such as pointerdown, pointerup, and click events. To measure the latency of this series of events, the events share the same interactionId.

An interactionId is only computed for the following event types belonging to a user interaction. It is 0 otherwise.

Event types User interaction
pointerdown, pointerup, click click / tap / drag
keydown, keyup key press


A number.


Using interactionId

The following example collects event duration for all events corresponding to an interaction. The eventLatencies map can then be used to find events with maximum duration for a user interaction, for example.

// The key is the interaction ID.
let = eventLatencies = {};

const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    if (entry.interactionId > 0) {
      const interactionId = entry.interactionId;
      if (!eventLatencies.has(interactionId)) {
        eventLatencies[interactionId] = [];

observer.observe({type: "event", buffered: true}); 

// Log events with maximum event duration for a user interaction
Object.entries(eventLatencies).forEach(([k, v]) => {


Event Timing API
# dom-performanceeventtiming-interactionid

Browser compatibility

BCD tables only load in the browser