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FingerprintJS

Build status Total downloads from NPM Current NPM version

Makes a website visitor identifier from a browser fingerprint. Unlike cookies and local storage, fingerprint stays the same in incognito/private mode and even when browser data is purged.

Quick start

Install from CDN

<script>
  function initFingerprintJS() {
    FingerprintJS.load().then(fp => {
      // The FingerprintJS agent is ready.
      // Get a visitor identifier when you'd like to.
      fp.get().then(result => {
        // This is the visitor identifier:
        const visitorId = result.visitorId;
        console.log(visitorId);
      });
    });
  }
</script>
<script
  async
  src="//cdn.jsdelivr.net/npm/@fingerprintjs/fingerprintjs@3/dist/fp.min.js"
  onload="initFingerprintJS()"
></script>

We recommend to upload the JS script to your server because AdBlock and other browser extensions can block the public script URL.

Alternatively you can install from NPM to use with Webpack/Rollup/Browserify

npm i @fingerprintjs/fingerprintjs
# or
yarn add @fingerprintjs/fingerprintjs
import FingerprintJS from '@fingerprintjs/fingerprintjs';

(async () => {
  // We recommend to call `load` at application startup.
  const fp = await FingerprintJS.load();

  // The FingerprintJS agent is ready.
  // Get a visitor identifier when you'd like to.
  const result = await fp.get();

  // This is the visitor identifier:
  const visitorId = result.visitorId;
  console.log(visitorId);
})();

📕 Full documentation

Upgrade to Pro version to get 99.5% identification accuracy

Pro screenshot

Open Source version

Pro version

Identification accuracy60%99.5%
Bot detection
Incognito / Private mode detection
Geolocation
Security
Server API
Webhooks

Pro result example:

{
  "requestId": "HFMlljrzKEiZmhUNDx7Z",
  "visitorId": "kHqPGWS1Mj18sZFsP8Wl",
  "visitorFound": true,
  "incognito": false,
  "bot": { "probability": 0.96 },
  "browserName": "Chrome",
  "browserVersion": "85.0.4183",
  "os": "Mac OS X",
  "osVersion": "10.15.6",
  "device": "Other",
  "ip": "192.65.67.131",
  "ipLocation": {
    "accuracyRadius": 100,
    "latitude": 37.409657,
    "longitude": -121.965467
    // ...
  }
}

🍿 Live demo

How to upgrade from Open Source to Pro in 30 seconds

📕 FingerprintJS Pro documentation

Open-source version reference

Installation

The library is shipped in various formats:

  • Global variable
    <script>
      function initFingerprintJS() {
        // ...
      }
    </script>
    <script
      async
      src="//cdn.jsdelivr.net/npm/@fingerprintjs/fingerprintjs@3/dist/fp.min.js"
      onload="initFingerprintJS()"
    ></script>
  • UMD
    require(
      ['//cdn.jsdelivr.net/npm/@fingerprintjs/fingerprintjs@3/dist/fp.umd.min.js'],
      (FingerprintJS) => {/* ... */}
    );
  • ECMAScript module
    import FingerprintJS from '@fingerprintjs/fingerprintjs';
  • CommonJS
    const FingerprintJS = require('@fingerprintjs/fingerprintjs');

API

  • FingerprintJS.load({ delayFallback?: number }): Promise<Agent>

    Builds an instance of Agent and waits a delay required for a proper operation. delayFallback is an optional parameter that sets duration (milliseconds) of the fallback for browsers that don't support requestIdleCallback; it has a good default value which we don't recommend to change.

  • agent.get({ debug?: boolean }): Promise<{ visitorId: string, components: {/* ... */} }>

    Gets the visitor identifier. debug: true prints debug messages to the console. visitorId is the visitor identifier. components is a dictionary of components that have formed the identifier; each value is an object like { value: any, duration: number } in case of success and { error: object, duration: number } in case of an unexpected error during getting the component.

  • FingerprintJS.hashComponents(components: object): string

    Converts a dictionary of components (described above) into a short hash string a.k.a. a visitor identifier. Designed for extending the library with your own components.

  • FingerprintJS.componentsToDebugString(components: object): string

    Converts a dictionary of components (described above) into human-friendly format.

Migrating from v2

Version policy

The library doesn't guarantee the same visitor identifier between versions, but will try to keep them the same as much as possible.

The documented JS API follows Semantic Versioning. Use undocumented features at your own risk.

Browser support

npx browserslist "> 1% in us"

Contribution

See the contribution guidelines to learn how to start a playground, test and build.

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