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.

This repository is a fork of FingerprintJS that was originally licensed under the MIT License. It has been rereleased as @sparkstone/fingerprintjs under the same MIT license.

Installation

You can install @sparkstone/fingerprintjs using your preferred package manager:

pnpm

pnpm add @sparkstone/fingerprintjs

npm

npm install @sparkstone/fingerprintjs

yarn

yarn add @sparkstone/fingerprintjs

Quick start

Here is a basic TypeScript example of how to use FingerprintJS:

import FingerprintJS from '@sparkstone/fingerprintjs'

// Initialize the agent at application startup.
const fp = await FingerprintJS.load()

// Get the visitor identifier when you need it.
const result = await fp.get()

// This is the visitor identifier:
console.log(result.visitorId)

📕 Full documentation

Migrating from v2

• Migration guide

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

Using Issues and Discussions publicly will help the open-source community and other users with similar issues.

Contributing

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

Changelog

3.5.0 switch to microbundle for building 3.5.1 remove confidence scoring, it was hard coded and fake?

// old pro scoring method -- upgrade to pro to get this score
function deriveProConfidenceScore(openConfidenceScore: number): number {
    return round(0.99 + 0.01 * openConfidenceScore, 0.0001)
}