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.

FingerprintJS is 100% open-source, but its accuracy is limited because it's only a client-side library without a backend.

Open Source library accuracy	Fingerprint Pro accuracy
FingerprintJS has limited accuracy (40% - 60%) and functionality, because it's not possible to do many things without a backend.	Fingerprint Pro is a high-scale device identity platform that has both client-side and server-side components and identifies browsers and mobile devices with a 99.5% accuracy. Fingerprint Pro is free for developers, production plans start at $200/mo.
FingerprintJS library demo: https://fingerprintjs.github.io/fingerprintjs	Fingerprint Pro demo: https://fingerprint.com/demo

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

⚛️ Sample usage with React on the StackBlitz platform

Use the free Pro version to get 99.5% identification accuracy

Fingerprint 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. Fingerprint Pro is available for Web, Android, iOS and other platforms.

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

Full product comparison:

	Open Source	Pro
Core Features
100% open source	yes	no1
Accuracy	up to 60%	99.5%
Standard fingerprint signals screen, os, device name	✓	✓
Advanced fingerprint signals canvas, audio, fonts	✓	✓
ID type	fingerprint	visitorID2
ID lifetime	several weeks	months/years
ID origin	client	server
ID collisions	common	rare
Mobile Native SDKs
Android	✓	✓
iOS	✓	✓
Flutter	-	✓
React Native	-	✓
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	–	✓
Ability to evade ad blockers	supported (NPM, own hosting)	supported (NPM + subdomain)
Geolocation based on IP address	–	✓
Operations
Data security	Your infrastructure	Encrypted at rest
Storage	Your infrastructure	Unlimited up to 1 yr
Regions	Your infrastructure	Hosting in US, EU and Mumbai
Compliance	Your infrastructure	GDPR, CCPA compliant3
SLA	No SLA	99.9% Uptime
Support	GitHub community	Support team via email, chat, and call-back within 1 business day

_{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. Fingerprint 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 prevention 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
    // ...
  },
  "firstSeenAt": {
    "global": "2022-03-16T11:26:45.362Z",
    "subscription": "2022-03-16T11:31:01.101Z"
  },
  "lastSeenAt": {
    "global": "2022-05-21T18:05:43.023Z",
    "subscription": "2022-05-20T05:41:29.926Z"
  }
}

🍿 Live demo

⏱ How to upgrade from Open Source to Pro in 30 seconds

📕 Fingerprint Pro documentation

▶️ Video: use Fingerprint 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 oss-support@fingerprint.com.

Contributing

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

Other products by Fingerprint

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