Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


Failed to load latest commit information.
Latest commit message
Commit time
March 23, 2023 19:55
February 21, 2023 08:47
December 18, 2020 14:17
October 21, 2020 08:39
January 31, 2023 17:03
February 23, 2023 10:55
January 18, 2023 18:06

FingerprintJS logo

Build status Current NPM version Monthly downloads from NPM Monthly downloads from jsDelivr

Discord server

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: Fingerprint Pro demo:

Quick start

  // Initialize the agent at application startup.
  const fpPromise = import('')
    .then(FingerprintJS => 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

📕 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.

Pro screenshot

Full product comparison:

Open Source Pro

Core Features

100% open sourceyesno1
Accuracyup to 60%99.5%
Standard fingerprint signals
screen, os, device name
Advanced fingerprint signals
canvas, audio, fonts
ID typefingerprintvisitorID2
ID lifetimeseveral weeksmonths/years
ID originclientserver
ID collisionscommonrare

Mobile Native SDKs

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 blockerssupported (NPM, own hosting)supported (NPM + subdomain)
based on IP address


Data securityYour infrastructureEncrypted at rest
StorageYour infrastructureUnlimited up to 1 yr
RegionsYour infrastructureHosting in US, EU and Mumbai
ComplianceYour infrastructureGDPR, CCPA compliant3
SLANo SLA99.9% Uptime
SupportGitHub communitySupport 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": "",
  "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

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


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

Other products by Fingerprint