Network Information API

Note: This feature is available in Web Workers.

The Network Information API provides information about the system's connection in terms of general connection type (e.g., 'wifi, 'cellular', etc.). This can be used to select high definition content or low definition content based on the user's connection.

The interface consists of a single NetworkInformation object, an instance of which is returned by the Navigator.connection property or the WorkerNavigator.connection property.



Provides information about the connection a device is using to communicate with the network and provides a means for scripts to be notified if the connection type changes. The NetworkInformation interface cannot be instantiated. It is instead accessed through the Navigator interface or the WorkerNavigator interface.

Extensions to other interfaces

Returns a NetworkInformation object containing information about the network connection of a device.

WorkerNavigator.connection Read only

Provides a NetworkInformation object containing information about the network connection of a device.


Detect connection changes

This example watches for changes to the user's connection.

let type = navigator.connection.effectiveType;

function updateConnectionStatus() {
    `Connection type changed from ${type} to ${navigator.connection.effectiveType}`,
  type = navigator.connection.effectiveType;

navigator.connection.addEventListener("change", updateConnectionStatus);

Preload large resources

The connection object is useful for deciding whether to preload resources that take large amounts of bandwidth or memory. This example would be called soon after page load to check for a connection type where preloading a video may not be desirable. If a cellular connection is found, then the preloadVideo flag is set to false. For simplicity and clarity, this example only tests for one connection type. A real-world use case would likely use a switch statement or some other method to check all of the possible values of NetworkInformation.type. Regardless of the type value you can get an estimate of connection speed through the NetworkInformation.effectiveType property.

let preloadVideo = true;
const connection = navigator.connection;
if (connection) {
  if (connection.effectiveType === "slow-2g") {
    preloadVideo = false;


Network Information API

Browser compatibility


BCD tables only load in the browser


BCD tables only load in the browser

See also