Smart Fingerprint

Lightweight browser fingerprint library with no server dependency.

It generates:

• stable fingerprint – more persistent device/browser traits
• full fingerprint – richer browser/device signals
• session fingerprint – tab/session scoped signal

Also includes:

• visitor ID generation
• fingerprint comparison (similarity + confidence)
• localStorage cache with TTL
• browser events
• ESM and UMD usage

---

Features

• Fast client-side fingerprint collection
• No server dependency
• Separate IDs for different stability levels:

stableId
fullId
sessionId

Additional per-method IDs in full fingerprint:

canvasId
webglId
fontId
audioId

Configurable signal collection:

Canvas
WebGL
Fonts
Audio (optional)

Built-in similarity scoring:

similarity
confidence

---

Installation

npm install @doxinger/smart-fingerprint

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CDN Usage

You can also use the library without npm.

jsDelivr

<script src="https://cdn.jsdelivr.net/npm/@doxinger/smart-fingerprint/src/main.umd.js"></script>

unpkg

<script src="https://unpkg.com/@doxinger/smart-fingerprint/src/main.umd.js"></script>

---

Quick Start (Node / Bundlers)

import SmartFingerprint from "@doxinger/smart-fingerprint";

const fp = await SmartFingerprint.get();

console.log(fp.visitorId);

---

Quick Start (Browser ESM)

<script type="module">
import SmartFingerprint from "@doxinger/smart-fingerprint";

const fp = await SmartFingerprint.get();

console.log(fp);
</script>

---

Quick Start (UMD)

<script src="https://cdn.jsdelivr.net/npm/@doxinger/smart-fingerprint/src/main.umd.js"></script>

<script>
SmartFingerprint.get().then(console.log);
</script>

---

API

SmartFingerprint.create(options?)

Creates a reusable instance.

const fp = SmartFingerprint.create({
  includeAudio: true
});

const result = await fp.get();

---

SmartFingerprint.get(options?)

Collects fingerprint and returns:

{
  "visitorId": "fp_...",
  "stableId": "st_...",
  "fullId": "fu_...",
  "sessionId": "ss_...",
  "confidence": 0.91,
  "stable": {},
  "full": {},
  "session": {},
  "normalized": {},
  "createdAt": 1710000000000
}

---

SmartFingerprint.refresh(options?)

Clears cache and recomputes fingerprint.

---

SmartFingerprint.compare(left, right)

Compares two fingerprints or normalized objects.

Returns:

{
  "similarity": 0.84,
  "confidence": 0.91,
  "sameVisitorLikely": true,
  "score": 82,
  "maxScore": 100
}

---

SmartFingerprint.on(eventName, handler)

Subscribe to events emitted by the library.

Supported event:

fingerprint:ready

Example:

const unsubscribe = SmartFingerprint.on("fingerprint:ready", (event) => {
  console.log(event.detail.result, event.detail.cached);
});

---

Options

Default configuration:

{
  includeCanvas: true,
  includeWebGL: true,
  includeFonts: true,
  includeAudio: false,
  autoCache: true,
  cacheKey: "__smart_fp_cache_v2__",
  cacheTtlMs: 1800000,
  emitEvents: true,
  debug: false
}

---

Full Fingerprint Methods

full.methods contains method-specific IDs.

{
  "canvasId": "cn_...",
  "webglId": "wg_...",
  "fontId": "ft_...",
  "audioId": "au_..."
}

---

Example Response

{
  "visitorId": "fp_8ef6b32e58a7d5e1",
  "stableId": "st_a1b2c3d4e5f60789",
  "fullId": "fu_2f7dc1254d0682af",
  "sessionId": "ss_84aa4f9f2d3c1b7e",
  "confidence": 0.91,
  "stable": {
    "id": "...",
    "raw": {},
    "normalized": {}
  },
  "full": {
    "id": "...",
    "raw": {},
    "normalized": {},
    "methods": {
      "canvasId": "cn_...",
      "webglId": "wg_...",
      "fontId": "ft_...",
      "audioId": null
    }
  },
  "session": {
    "id": "...",
    "raw": {},
    "normalized": {}
  },
  "normalized": {},
  "createdAt": 1710000000000
}

---

Demo

• https://doxinger.github.io/smart-fingerprint/

Notes

• Fingerprints can change after browser updates, driver/GPU changes, privacy settings, or anti-fingerprinting tools.
• Use compare() and similarity for probabilistic matching instead of strict equality checks.
• Respect user privacy laws and local regulations when using browser fingerprinting in production.

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License

Apache-2.0