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.

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Quick start

<script>
  // Initialize the agent at application startup.
  const fpPromise = import('https://openfpcdn.io/fingerprintjs/v3')
    .then(FingerprintJS => FingerprintJS.load())

  // Get the visitor identifier when you need it.
  fpPromise
    .then(fp => fp.get())
    .then(result => {
      // This is the visitor identifier:
      const visitorId = result.visitorId
      console.log(visitorId)
    })
</script>

Run this code

📕 Full documentation

Upgrade to the Pro version 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 the 99.5% identification accuracy.

Pro plans start at $0/month - no credit card required.

Full product comparison:

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

2. 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 less stable across > 4 week time intervals.

3. FingerprintJS Pro 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,
  "confidence": { "score": 0.995 },
  "incognito": false,
  "browserName": "Chrome",
  "browserVersion": "92.0.4515.107",
  "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

▶️ Video: use FingerprintJS Pro to prevent multiple signups

Migrating from v2

• Migration guide
• V2 documentation

Version policy

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

Supported browsers

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

Where to get support

Thanks to our series B funding, we are happy to provide technical support for our open-source FingerprintJS library. We recommend using GitHub Issues to submit bugs or Discussions to ask questions. Using issues and discussions publicly will help the open-source community and other users with similar issues. However, if you require private support, please email us at [email protected].

Contributing

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

Other products by FingerprintJS

• BotD -- Easy to use JavaScript bot detection
• AEV -- Android App Environment Verification API