WebRTC Leak Test
Even with a VPN, your browser's WebRTC can reveal your real IP while negotiating P2P connections. This test negotiates a session against public STUN servers, classifies the candidates and tells you whether your local IP is exposed — with a copyable report and honest explanation.
What the WebRTC leak is: even with a VPN, your browser's WebRTC can reveal your real IP while negotiating P2P connections (video calls, browser torrents). Modern browsers mitigate it with mDNS — green means you're covered; red means you should block WebRTC via your VPN's extension or settings.
Built by
Miguel Ángel Colorado Marin (MACM)
Built by
Miguel Ángel Colorado Marin (MACM)
Full-Stack Developer · Guadalajara, España
I develop web apps, digital tools and full projects — from design to deployment.
The WebRTC leak is the classic VPN hole: your browser's WebRTC creates P2P connections and queries STUN servers that hand back your exit IP — and sometimes your local IP. An attacker only needs JavaScript to open an RTCPeerConnection and read those candidates. This test does exactly what a malicious page would (minus the malice): negotiates an ICE session against public STUN servers, classifies every candidate per the protocol standard, and tells you plainly whether your local IP is exposed. Modern browsers protect it with mDNS — green means covered; red means block WebRTC via your VPN's extension. Everything runs locally with a parser verified by a 21-test bank.
Features
- ✓Real ICE candidate collection against public STUN servers (Google and Cloudflare)
- ✓Candidate classification: host, srflx, prflx and relay badges
- ✓Local IP exposure detection with mDNS privacy status
- ✓Green verdict when protected, red when your local IP leaks
- ✓Copyable JSON report for audits
How to check for a WebRTC leak?
- 1
Click «Check WebRTC leak»
A test ICE session is negotiated in your browser: no uploads, no servers of ours.
- 2
Read the verdict
Green = mDNS only (protected). Red = your real local IP showed up in the candidates.
- 3
Check the reference public IP
The IP STUN returns is your exit IP: compare it with your VPN's expected one.
- 4
Act on red
Block WebRTC via your VPN extension or browser settings, and re-check.
Frequently asked questions
What is this test for if I use a VPN?
To verify your VPN mitigates the leak. Good VPNs block WebRTC via their extension; mediocre ones don't, and your real IP leaks on any JavaScript site. This test is the 5-second check of whether your real setup protects you.
Why is my test green without a VPN?
Because modern browsers apply the standard mitigation by default: local candidates use mDNS (.local) instead of your real local IP. Green confirms your browser's default protection is working.
Is anything sent to your servers during the test?
No. The ICE negotiation runs against Google's and Cloudflare's public STUN servers — the same ones any video call uses — and the analysis happens in your browser. No request to miguelacm.es while the test runs.
Related tools
Embed WebRTC Leak Test on your site
Add WebRTC Leak Test to any web page with a simple iframe. Free, with attribution to miguelacm.es.
<iframe
src="https://miguelacm.es/embed/webrtc-leak-test"
width="100%"
height="700"
frameborder="0"
title="WebRTC Leak Test — miguelacm.es"
></iframe>