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    3.2.0 • Public • Published


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    FingerprintJS is a browser fingerprinting library that queries browser attributes and computes a hashed visitor identifier from them. Unlike cookies and local storage, a fingerprint stays the same in incognito/private mode and even when browser data is purged.

    View Our Demo.

    Quick start

    Install from CDN

      function initFingerprintJS() {
        // Initialize an agent at application startup.
        const fpPromise = FingerprintJS.load()
        // Get the visitor identifier when you need it.
          .then(fp => fp.get())
          .then(result => {
            // This is the visitor identifier:
            const visitorId = result.visitorId

    Run this code

    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'
    // Initialize an agent at application startup.
    const fpPromise = FingerprintJS.load()
    ;(async () => {
      // Get the visitor identifier when you need it.
      const fp = await fpPromise
      const result = await fp.get()
      // This is the visitor identifier:
      const visitorId = result.visitorId

    Run this code

    📕 Full documentation

    Switch to Pro version for free to get 99.5% identification accuracy

    FingerprintJS Pro is a professional visitor identification service that processes all information server-side and transmits it securely to your servers using server-to-server APIs. Pro combines browser fingerprinting with vast amounts of auxiliary data (IP addresses, time of visit patterns, URL changes and more) to be able to reliably deduplicate different users that have identical devices, resulting in 99.5% identification accuracy.

    You can use Pro FREE for up to 1,000 unique monthly visitors - no credit card required.

    Pro screenshot

    Full product comparison:

    Open Source Pro

    Core Features

    100% Open-source yes no*
    Standard fingerprint signals
    screen, os, device name
    Advanced fingerprint signals
    canvas, audio, fonts
    ID type fingerprint visitorID**
    ID lifetime several weeks months/years
    ID origin client server
    ID collisions common rare

    Additional Features

    Incognito mode detection
    works in all modern browsers - see our full list of browsers supported
    Server-side accuracy increase
    based on additional server-side signals, such as TLS crypto support, ipv4/v6 data and others
    Query API & realtime Webhooks
    build flexible workflows
    based on IP address


    Data security Your infrastructure Encrypted at rest
    Storage Your infrastructure Unlimited up to 1 yr
    Regions Your infrastructure Hosting in US and EU
    Compliance Your infrastructure GDPR, CCPA compliant***
    SLA No SLA 99.9% Uptime
    Support GitHub community Support team via email, chat, and call-back within 1 business day

    * Pro uses the open source fingerprinting library as well as proprietary technology for increased accuracy and stability.

    ** VisitorIDs, in comparison to fingerprints, include server side techniques, are deduplicated and utilize fuzzy matching to result in a more accurate and stable identifier. Fingerprint hashes rely on an exact match across all browser attributes, making them unstable across > 2 week time intervals.

    *** FingerprintJS is GDPR and CCPA compliant as the data processor. You still need to be compliant as the data controller and use the identification for fraud under legitimate interest or ask for user consent.

    Pro result example:

      "requestId": "HFMlljrzKEiZmhUNDx7Z",
      "visitorId": "kHqPGWS1Mj18sZFsP8Wl",
      "visitorFound": true,
      "incognito": false,
      "browserName": "Chrome",
      "browserVersion": "85.0.4183",
      "os": "Mac OS X",
      "osVersion": "10.15.6",
      "device": "Other",
      "ip": "",
      "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

    ▶️ Video: use FingerprintJS Pro to prevent multiple signups

    Migrating from v2

    Version policy

    See the compatibility policy for the API and visitor identifiers in the version policy guide.

    Browser support

    The library supports all popular browsers. See more details and learn how to run the library in old browsers in the browser support guide.


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


    npm i @fingerprintjs/fingerprintjs

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