1.0.5 • Public • Published

Private or Incognito Browsing Detector / Paywall

Javascript code to Detect Private and Incognito Browsing Mode. You can implement a Paywall System by detecting private or incognito browsing.

Implementing a Paywall System for Private or Incognito Browsing Mode

You can implement a Paywall System with Javascript blocking the Private or Incognito browsing in your Website using this code.

This detector can identify Bots Browsing your application and you can turn on/turn off this detection.
With Bot detector on, when Googlebot visit your page you don't block it!

How to use


You can include the /dist/BrowsingModeDetector.js or /dist/BrowsingModeDetector.gz via <script> tag direct on your application or via npm:

npm i js-detect-incognito-private-browsing -S

Implementing behaviour based on Browsing Mode:

Passing a callback to BrowsingModeDetector.do() method you can implement the needed behaviour testing the returned value:

var myCallback = function (browsingInIncognitoMode, BrowsingModeDetectorInstance) {
    console.log('Is private?', browsingInIncognitoMode);
    console.log('Browsing Mode:', BrowsingModeDetectorInstance.getBrowsingMode());
    if (browsingInIncognitoMode) {
        // Incognito, Private mode detected
    // Normal mode detected
var BrowsingModeDetector = new BrowsingModeDetector();

Advanced use of callbacks:

You can use a default callback combined with specific callbacks for each browsing method:

var callbackWhenNormalMode = function () {
    console.log('callbackWhenNormalMode called');
var callbackWhenIncognitoOrPrivateMode = function () {
var defaultCallback = function (browsingInIncognitoMode) {
    console.log('This callback will be called either private or normal mode detected, optional though. Is private or incognito?', browsingInIncognitoMode);
var BrowsingModeDetector = new BrowsingModeDetector();
    .do(defaultCallback); // optional if callbacks are given for normal and private modes

Possible callbacks arrangements:

  • Only Default Callback using .do(callback) method
  • Callback for Normal Mode .setCallbackForNormalMode(callback) combined with Private Mode .setCallbackForIncognitoOrPrivateMode(callback)
  • Default Callback combined with Normal Mode and Private/Incognito Mode Callbacks

On callbacks you can use the .getBrowsingMode() if necessary, because a instance of BrowsingModeDetector is passed for all callback functions:

var callbackWhenNormalMode = function (BrowsingModeDetectorInstance) {
    console.log('callbackWhenNormalMode called when', BrowsingModeDetectorInstance.getBrowsingMode());
var callbackWhenIncognitoOrPrivateMode = function (BrowsingModeDetectorInstance) {
    console.log('callbackWhenIncognitoOrPrivateMode called when', BrowsingModeDetectorInstance.getBrowsingMode());
var defaultCallback = function (browsingInIncognitoMode, BrowsingModeDetectorInstance) {
    console.log('Is private or incognito?', browsingInIncognitoMode);
    if (BrowsingModeDetectorInstance.getBrowsingMode() === BrowsingModeDetectorInstance.BROWSING_NORMAL_MODE) {
        console.log('Do something if is NORMAL_MODE!');
    } else {
        console.log('Do something if is INCOGNITO_PRIVATE_MODE!');

Note that will be passed a BrowsingModeDetector instance for each user defined callback and for default callback to .do(callback) method will be passed as first param of callback a boolean value meaning browsing in incognito mode when true and a BrowsingModeDetector instance as second param of callback.

Ignoring (or not) browsing mode for Bots:

If you have a Website, probably you want to ignore if Bots are browsing:

var BrowsingModeDetector = new BrowsingModeDetector();
// or BrowsingModeDetector.ignoringBots().do(myCallback);

Or testing for Bots too(e.g: if Googlebot browse your site, the detector will return that browsing mode is private):

var BrowsingModeDetector = new BrowsingModeDetector();

Bot Browsing Detection:

You can test if is a Bot browsing in two ways:

var isBot = BrowsingModeDetector.isBotBrowsing();
console.log('Is Bot:', isBot);

Or passing a callback to isBotBrowsing method:

var isBot = BrowsingModeDetector.isBotBrowsing(function(isBot) {
    console.log('Is Bot:', isBot);


For a complete example with JS and HTML see the /example/index.html file.

Compiling the code:

Clone this repo and you can use npm and webpack to compile the code. Install the requirements:

git clone https://github.com/Maykonn/js-detect-incognito-private-browsing-paywall
npm install

In your dev environment you can run (will compile the code and open the example app at localhost:8080/):

npm run start

Build the code to production at /dist directory (minify, uglify, remove comments, logs, etc):

npm run build

The npm run build command will generate two file at /dist directory, BrowsingModeDetector.gz and BrowsingModeDetector.js.


You can contribute cloning this repository from github clicking here. So, you just need to create a new branch using a name related to the new functionality which you'll create.
And after finish your code, you just need to create a pull request which will be revised, merged to master(if the code doesn't break the lib) branch and published a new release of this library.

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npm i js-detect-incognito-private-browsing

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