WebRTC Fingerprinting

WebRTC fingerprinting creates a peer connection and observes ICE candidate types. This reveals network topology without exposing raw IP addresses.

How it works

Neoprint creates an RTCPeerConnection with no ICE servers, generates an offer, and collects ICE candidates. Only candidate types are recorded (not IP addresses).

Collected signals

Signal	Description
candidateCount	Number of ICE candidates generated
ipTypes	Unique types: mdns, private, public
hasMdns	Whether mDNS candidates are present
hasPrivate	Whether private IP candidates are present

Privacy

Raw IP addresses are never stored or exposed. Only the type classification (mdns/private/public) is recorded.

Entropy and stability

Property	Value
Entropy	~4 bits
Stability	0.50
Typical duration	50-100ms

WebRTC is the slowest collector due to ICE candidate gathering. Neoprint resolves after the first candidate arrives (+ 50ms batch window) instead of waiting for the full gathering process.

Excluded in privacy mode.

Usage

const fp = await neoprint.get({ collectors: ['webrtc'] })
const rtc = fp.components.webrtc.value

console.log(rtc.candidateCount)  // 2
console.log(rtc.ipTypes)         // ["mdns"]
console.log(rtc.hasMdns)         // true