Cross-Browser Identification

Identify the same user across Chrome, Firefox, Safari, and Edge on the same device.

How It Works

The crossBrowserId uses only hardware-level signals that don't change between browsers. All values are normalized to absorb browser-specific differences:

• GPU vendor and renderer — ANGLE wrapper stripped, PCI IDs removed, model numbers stripped to family name
• WebGL rendering hash — 3D scene pixel output, identical cross-browser on same GPU (~8 bits extra entropy)
• WebGL hardware params — maxRenderbufferSize, maxFragmentUniformVectors, maxVertexAttribs, etc.
• WebGPU limits — maxTextureDimension, maxBufferSize, etc. (when available)
• CPU math precision — rounded to 8 significant digits (absorbs V8 vs SpiderMonkey vs JSC diffs)
• Display properties — DPR, HDR, color gamut, touch capability (not screen dimensions — Safari reports viewport size)
• Timezone and locale — locale normalized to base language (pl-PL → pl)
• Installed fonts — browser-bundled fonts filtered out (Edge adds Roboto)
• Audio sample rate (hardware-dependent)

What's excluded

These signals differ per browser on the same device and are not used in crossBrowserId:

Signal	Why excluded
User-Agent, plugins, extensions	Browser-specific by definition
Canvas, WebGL extensions	Engine-dependent rendering
Storage quotas, permissions	Differ per browser profile
hardwareConcurrency	Safari caps to 8 on high-core CPUs
deviceMemory	Safari doesn't expose this API
colorDepth / pixelDepth	Chrome 30 vs Safari 24 on same display
Locale format	Chrome pl vs Edge/Firefox pl-PL (normalized)
GPU model number	Firefox anti-fingerprinting reports different model than Chrome/Edge
Speech voices	Completely different voice lists per engine (Chrome 21, Edge 25, Firefox 4 on same Windows PC)
Browser-bundled fonts	Edge adds Roboto, Chrome may add Noto
Hardware perf timings	Vary with CPU load, thermal state, GC timing
Screen width/height	Safari reports viewport size instead of physical resolution

Usage

import neoprint from '@neoprintjs/core'

const fp = await neoprint.get()
console.log(fp.crossBrowserId) // Same on Chrome, Firefox, Safari, Edge

// Send to your server to link browser profiles
await fetch('/api/link-device', {
  method: 'POST',
  body: JSON.stringify({ crossBrowserId: fp.crossBrowserId })
})

Accuracy Considerations

Cross-browser ID is medium collision resistance — it's possible for two different devices with identical hardware to produce the same ID. Best used as one factor in a multi-signal identification system.

Signals that help differentiation:

• Different GPU families → different renderer and hardware limits
• Different font sets installed at OS level
• Different CPU architectures → different math precision and perf ratios
• Different screen resolutions and DPR
• Different timezones and locales
• WebGPU limits (when available) add significant hardware detail