Free WebRTC Leak Test

What Is a WebRTC Leak?

WebRTC (Web Real-Time Communication) is the browser API that powers Google Meet, Zoom in the browser, Discord voice, WhatsApp Web calls, and most screen-sharing tools. To negotiate a peer-to-peer connection, WebRTC needs to know every IP your device has. It does that by asking a STUN server over UDP — and critically, the STUN request can bypass your VPN tunnel unless the VPN is specifically built to catch it. That is the leak: a website with a few lines of WebRTC JavaScript can see your real public and local IP addresses, even when your VPN says you are protected.

This tool runs a STUN query inside your browser (no data leaves your machine) and reports every IP WebRTC exposes — so you know exactly how much privacy your setup is really giving you.

How to Read Your Result

• Public IP — should match your VPN server. If you see your ISP-assigned IP here, your VPN is leaking.
• Local IPs — your private network addresses (192.168.x, 10.x, 172.16-31.x). Chrome since version 76 and Safari on recent macOS replace these with a hashed .local string by default; that hash is safe and cannot be tracked.
• IPv6 — many VPNs tunnel only IPv4. If your ISP gives you IPv6 and your VPN does not handle it, WebRTC can leak v6 even when v4 looks clean.

Why WebRTC Leaks Even With a VPN On

A regular VPN reroutes your browser's HTTP and DNS traffic through an encrypted tunnel. WebRTC uses a different channel: direct UDP to a STUN server. Unless the VPN intercepts that UDP traffic specifically, your real IPs slip through. This is why not every VPN is equal — the good ones (Mullvad, ProtonVPN, NordVPN, ExpressVPN) catch WebRTC; many cheap or free VPNs do not.

The practical fix is either (a) pick a VPN that blocks WebRTC at the app or tunnel level, or (b) disable WebRTC in the browser. Disabling is a bigger trade-off than most guides admit: it also breaks every browser-based video call.

Per-Browser Fix Summary

• Chrome / Edge — no built-in toggle. Install the official Google "WebRTC Network Limiter" extension, or use uBlock Origin with its Prevent WebRTC from leaking local IP option checked.
• Firefox — about:config → set media.peerconnection.enabled to false. This is the cleanest off switch but disables video calls.
• Brave — brave://settings/privacy → "WebRTC IP handling policy" → Disable Non-Proxied UDP. Only major browser with an in-UI control.
• Safari — disable "WebRTC Platform UDP Sockets" under Develop > Feature Flags (macOS) or toggle "WebRTC mDNS ICE candidates" on iOS.
• Any browser — a VPN with correct WebRTC handling fixes this transparently without disabling video calls.

Seeing a .local Address? That Is Not a Leak

Since Chrome 76 (mid-2019) and on recent versions of Safari, your local IP is replaced by a hashed string like a1b2c3d4-e5f6-7890-abcd-ef1234567890.local. This mDNS ICE candidate is a privacy feature, not a leak — the hash rotates and cannot be resolved outside your local network. If that is the only thing in the Local IPs field, your browser is doing the right thing.

Common Myths Worth Busting

• "Incognito mode stops WebRTC leaks." False. Incognito only clears local history and cookies. WebRTC still runs and still leaks.
• "Any VPN will stop WebRTC leaks." False. Many free and budget VPNs route TCP through the tunnel but let WebRTC UDP slip past.
• "I must disable WebRTC to be safe." Not always. A good VPN routes WebRTC correctly and preserves video calls.
• "The .local string is my real IP." No. It is a Chrome mDNS hash that cannot be tracked or resolved remotely.

Read the Full Guide

For a deeper walkthrough with screenshots, a fix video, and browser-by-browser troubleshooting, see our full article: What Is a WebRTC Leak and How to Fix It.

Related Tools

• Latency Checker — network diagnostics companion
• Webcam Test — uses the same getUserMedia/WebRTC APIs
• Microphone Test — WebRTC audio capture
• Password Generator — privacy-focused sibling tool