Nearsighted Paramecium Multiverse
Wondering what’s next for npm?Check out our public roadmap! »


3.1.0 • Public • Published

About this fork

The goal of this fork is to create a modular build of Fingerprint2. The benefit is easier reuse and composition. With tree-shaking, you can also expect smaller build output because it's easier to detect unused code.

FPJS logo

build status gitter chat total downloads from NPM Current NPM version

Try FPJS PRO - 99.5% identification accuracy


  • NPM: npm install fingerprintjs2-modular
  • Yarn: yarn add fingerprintjs2-modular


import Fingerprint2 from 'fingerprintjs2-modular'
if (window.requestIdleCallback) {
  requestIdleCallback(function() {
    Fingerprint2(function(components) {
      console.log(components) // an array of components: {key: ..., value: ...}
} else {
  setTimeout(function() {
    Fingerprint2(function(components) {
      console.log(components) // an array of components: {key: ..., value: ...}
  }, 500)

Note: You should not run fingerprinting directly on or after page load. Rather, delay it for a few milliseconds with setTimeout or requestIdleCallback to ensure consistent fingerprints. See #307, #254, and others.

On my machine (MBP 2013 Core i5) + Chrome 46 the default FP process takes about 80-100ms. If you use extendedJsFonts option this time will increase up to 2000ms (cold font cache).

To speed up fingerprint computation, you can exclude font detection (~ 40ms), canvas fingerprint (~ 10ms), WebGL fingerprint (~ 35 ms), and Audio fingerprint (~30 ms).


To choose which components to include in the fingerprint, pass a list to the Fingerprint2 function

import Fingerprint2, { canvas, userAgent, webgl } from 'fingerprintjs2-modular'
  components: [canvas, userAgent, webgl],
  // other options

With tree-shaking (built-in with most modern build tools), imports like these will automatically eliminate all unused fingerprinting code, which should drastically decrease the output size.

For the default options, please see the source code (look for var defaultOptions = {).

Recommended Components

You can also use all recommended components recommended import

import Fingerprint2, { recommended } from 'fingerprintjs2-modular'
  components: recommended,
  // other options

Custom Components

All components are simple objects with key (component name) and getData(done, options) properties. You can provide the custom components along with any of the used built-in components.

// myCustomComponent.js
const myCustomComponent = {
  key: 'customKey',
  getData: (done, options) => {
    done('infos ...')
// main.js
import Fingerprint2, { recommended } from 'fingerprintjs2-modular'
import myCustomComponent from './myCustomComponent'
  components: [...recommended, myCustomComponent],
  // other options

Extended Fonts List

By default, JS font detection will only detect up to 65 installed fonts. If you want to improve the font detection by passing the extendedFontsList.

To use extended fonts list, import the extendedFontsList array from fonts component. This will increase the number of detectable fonts to ~500.

import Fingerprint2, { fonts, /*, other components */, extendedFontsList } from 'fingerprintjs2-modular'
  components: [fonts /*, other components */],
  fonts: {
    userDefinedFonts: extendedFontsList,
  // other options

Note that this option increases fingerprint duration from about 80-100ms to up to 2000ms (cold font cache). It can incur even more overhead on mobile Firefox browsers, which is much slower in font detection, so use it with caution on mobile devices.

The extendedFontsList is an array, so it can be easily extended to add more custom fonts:

  components: [fonts /*, other components */],
  fonts: {
    userDefinedFonts: [
      'Nimbus Mono',
  // other options


Specifies an array of user-defined fonts to increase font fingerprint entropy even more.

While hundreds of the most popular fonts are included in the extended font list, you may wish to increase the entropy of the font fingerprint by specifying the userDefinedFonts option as an array of font names, but make sure to call the Fingerprint function after the page load, and not before, otherwise font detection might not work properly and in a result returned hash might be different every time you reloaded the page.

    userDefinedFonts: ['Nimbus Mono', 'Junicode', 'Presto'],
  function(components) {},


Specifies the dom element ID to be used for swf embedding (flash fonts)


Specifies the path to the FontList.swf (flash fonts)

screen.detectScreenOrientation (default: true)

plugins.sortPluginsFor (default: [/palemoon/i])

Some browsers randomise plugin order. You can give a list of user agent regexes for which plugins should be sorted.


Skip IE plugin enumeration/detection

audio.excludeIOS11 (default: true)

iOS 11 prevents audio fingerprinting unless started from a user interaction (screen tap), preventing the fingerprinting process from finishing. If you're sure you start fingerprinting from a user interaction event handler, you may enable audio fingerprinting on iOS 11.

audio.timeout (default: 1000)

maximum time allowed for 'audio' component


To use Flash font enumeration, make sure you have swfobject available. If you don't, the library will skip the Flash part entirely.


Function that is called with each component value that may be used to modify component values before computing the fingerprint. For example: strip browser version from user agent.

    preprocessor: function(key, value) {
      if (key == 'userAgent') {
        var parser = new UAParser(value) //
        var userAgentMinusVersion =
          parser.getOS().name + ' ' + parser.getBrowser().name
        return userAgentMinusVersion
      return value
  function(components) {
    // userAgent component will contain string processed with our function. For example: Windows Chrome

Excluding components

The most straight-forward way to exclude components is to not pass them to the components list. If you want to use the recommended list, but not use all of the components, a workaround is to filter out the unwanted components

import Fingerprint2, { recommended } from 'fingerprintjs2-modular'
const excludedComponentKeys = ['userAgent', 'language']
  components: recommended.filter(
    (component) => !excludedComponentKeys.includes(component.key),
  // other options

Note: the above example uses Array.prototype.includes(), which is ES2015 feature and is not supported in older browsers. Make sure to use to include a polyfill or use a different method to filter the components.


The constants used for unavailable, error'd, or excluded components' values.

  • NOT_AVAILABLE: Component value if the browser doesn't support the API the component uses (e.g. enumerateDevices) or the browser doesn't provide a useful value (e.g. deviceMemory).
  • ERROR: The component function threw an error.
  • EXCLUDED: The component was excluded.

If you want to use the value of constant, or compare against the value, import them as

import { NOT_AVAILABLE, ERROR, EXCLUDED } from 'fingerprintjs2-modular'

Upgrade guide from 2.0.0

Recommended components and custom components

Expecting all components to be passed as options.components array, for example:

import Fingerprint2, { recommended } from 'fingerprintjs2-modular'
  components: recommended,
  // other options

Excluded components

Pass only options.components which you want to use. If importing the recommended components array, filter out the array to exclude the unwanted components.


The constants are not configurable. To use the constants in your custom components or to compare against the constant, import constants as

import { NOT_AVAILABLE, ERROR, EXCLUDED } from 'fingerprintjs2-modular'


Fingerprint2.x64hash128 is not exposed anymore. Import the function as

import { x64hash128 } from 'fingerprintjs2-modular'

Or if you prefer, you can use a different hash function.

Backwards compatibility mode

The backwards compatibility mode function (Fingerprint2.getV18) was removed. If you wish to keep using the exact implementation, you can copy it to your codebase.


The Fingerprint2.getPromise was removed. To support it in all browsers, we would have to provide a polyfill. The function was a simple wrapper around new Promise, and you can replicate it with this code:

const fingerprintPromise = new Promise((resolve) => {
  Fingerprint2(options, resolve)

Upgrade guide from 1.8.2 to 2.0.0

Backwards compatibility mode

Fingerprintjs2 v2.0 provides a v1.8 compatibility wrapper that keeps user's fingerprints identical to the ones generated with v1.8. Note that we will drop this wrapper at some point.

Note that the options parameter must be provided in v2.0 syntax.

// options must be provided in v2.0 syntax
Fingerprint2.getV18(options, function(result, components) {
  // result is murmur hash fingerprint
  // components is array of {key: 'foo', value: 'component value'}

get and getPromise

Fingerprint2.get is now a static function. It replaces new Fingerprint2().get. It will not hash the result by default anymore.

var options = {}
Fingerprint2.get(options, function (components) {
  // components is array of {key: 'foo', value: 'component value'}

// or

Fingerprint2.getPromise(options).then(function (components) {
  // components is array of {key: 'foo', value: 'component value'}

Fingerprint2 ships with the murmur hash function that you may use to create a hash fingerprint:

Fingerprint2.get(options, function (components) {
    var values = (component) { return component.value })
    var murmur = Fingerprint2.x64hash128(values.join(''), 31)


Before exclusion was done by putting an individual excludes like excludeTouchSupport: true in the options.

To exclude a component now, put its key inside the excludes object in options

var options = {excludes: {touchSupport: true}}

Custom Entropy Function

options.customEntropyFunction and customKey have been replaced with a extension friendly, stable alternative. The new contract allows for async sources as well. See below for component definition. options.extraComponents should contain an array with custom components.

var options = {
    extraComponents : [
        {key: 'customKey', getData: function (done, options) {
            done('infos ...')

jsfonts and flashFonts

jsfonts has been renamed into fonts. fontsFlash and fonts are now separate components. fontsFlash is excluded by default.

Consistent names for components

Components keys are now all camelCase. Example 'userAgent' -> 'userAgent'


Fingerprint2.x64hash128 static function is now exposed

Error constants are exposed and configurable

Fingerprint2.NOT_AVAILABLE = 'not available'
Fingerprint2.ERROR = 'error'
Fingerprint2.EXCLUDED = 'excluded'


audioTimeout is an option, default 1000ms



A components is an object with at least key and getData keys, example:

{key: 'userAgent', getData: UserAgent, pauseBefore: false}

getData value is the components function.

Component function

A components function takes done as first argument, and options as an optional second argument. It must call done exactly once with a value that can be cast to a String. It must wrap all unreachable code (setTimeout, requestAnimationFrame, etc) in its own try catch, it should use catch as an opportunity to give a unique value to done

function (done, options) {


Unit tests are in specs/specs.js

npm test to launch the tests, it requires phanomjs install

To run the tests in the browser, launch spec_runner.html


Future development

Many more fingerprinting sources will be implemented, such as (in no particular order)

  • Multi-monitor detection,
  • Internal HashTable implementation detection
  • WebRTC fingerprinting
  • Math constants
  • Accessibility fingerprinting
  • Camera information
  • DRM support
  • Accelerometer support
  • Virtual keyboards
  • List of supported gestures (for touch-enabled devices)
  • Pixel density
  • Video and audio codecs availability

To recompile the FontList.swf file:

  • Download Adobe Flex SDK
  • Unzip it, add the bin/ directory to your $PATH (mxmlc binary should be in path)
  • Run make

Talk about the library (in Russian) on FrontEnd Conf 2015

License: MIT or Apache, whichever you prefer





npm i fingerprintjs2-modular

DownloadsWeekly Downloads






Unpacked Size

152 kB

Total Files


Last publish


  • avatar