What is a WebRTC leak?

WebRTC is a browser technology for real-time audio, video, and data. To connect peers directly, it gathers your device's IP addresses - including your real public IP via STUN servers - and can expose them to web pages through JavaScript, even when a VPN is active. That exposure is a WebRTC leak.

Can a VPN still leak my IP through WebRTC?

Yes. A VPN routes your normal traffic through an encrypted tunnel, but WebRTC can use STUN to discover your real public IP outside that tunnel. If the IP WebRTC reveals differs from the IP the rest of your connection uses, your real location is exposed despite the VPN.

How does this test work?

Your browser opens a WebRTC peer connection against public STUN servers and collects the resulting ICE candidates. Host candidates reveal local network addresses, server-reflexive (srflx) candidates reveal the public IP seen by the STUN server, and relay candidates use a TURN relay. We compare any public IP found against your known public IP to flag a leak.

How do I prevent WebRTC leaks?

Use a VPN or browser extension that disables or proxies WebRTC, turn off WebRTC in your browser's settings or via an extension, or use a browser that routes WebRTC through the VPN tunnel. Re-run this test afterwards to confirm your real IP is no longer exposed.

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WebRTC Leak Test

A WebRTC leak exposes your real public IP to websites through browser peer-connection APIs, even when a VPN is connected. This test gathers ICE candidates via public STUN servers and flags any public IP that differs from the address your VPN should be showing.

How WebRTC leaks work

WebRTC enables direct peer-to-peer connections in the browser for video calls, file sharing, and gaming. To find the best path between peers, it runs the ICE process, which gathers candidate addresses for your device.

To discover your public-facing address, WebRTC queries a STUN server, which reports back the IP it sees - your real public IP. Because this happens at the browser level, it can bypass a VPN that only tunnels regular traffic, exposing the address the VPN is supposed to hide.

Web pages can read these candidates with a few lines of JavaScript, with no permission prompt.

Frequently Asked Questions

What is a WebRTC leak?: WebRTC is a browser technology for real-time audio, video, and data. To connect peers directly, it gathers your device's IP addresses - including your real public IP via STUN servers - and can expose them to web pages through JavaScript, even when a VPN is active. That exposure is a WebRTC leak.
Can a VPN still leak my IP through WebRTC?: Yes. A VPN routes your normal traffic through an encrypted tunnel, but WebRTC can use STUN to discover your real public IP outside that tunnel. If the IP WebRTC reveals differs from the IP the rest of your connection uses, your real location is exposed despite the VPN.
How does this test work?: Your browser opens a WebRTC peer connection against public STUN servers and collects the resulting ICE candidates. Host candidates reveal local network addresses, server-reflexive (srflx) candidates reveal the public IP seen by the STUN server, and relay candidates use a TURN relay. We compare any public IP found against your known public IP to flag a leak.
What are mDNS candidates?: Modern browsers replace raw local IPs in host candidates with randomized .local hostnames (mDNS) to protect your privacy. When you see an mDNS candidate, your local IP is being hidden - that's the secure, expected behaviour.
How do I prevent WebRTC leaks?: Use a VPN or browser extension that disables or proxies WebRTC, turn off WebRTC in your browser's settings or via an extension, or use a browser that routes WebRTC through the VPN tunnel. Re-run this test afterwards to confirm your real IP is no longer exposed.

Related Tools

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WebRTC Leak Test

How WebRTC leaks work

Web pages can read these candidates with a few lines of JavaScript, with no permission prompt.

Frequently Asked Questions

What is a WebRTC leak?: WebRTC is a browser technology for real-time audio, video, and data. To connect peers directly, it gathers your device's IP addresses - including your real public IP via STUN servers - and can expose them to web pages through JavaScript, even when a VPN is active. That exposure is a WebRTC leak.
Can a VPN still leak my IP through WebRTC?: Yes. A VPN routes your normal traffic through an encrypted tunnel, but WebRTC can use STUN to discover your real public IP outside that tunnel. If the IP WebRTC reveals differs from the IP the rest of your connection uses, your real location is exposed despite the VPN.
How does this test work?: Your browser opens a WebRTC peer connection against public STUN servers and collects the resulting ICE candidates. Host candidates reveal local network addresses, server-reflexive (srflx) candidates reveal the public IP seen by the STUN server, and relay candidates use a TURN relay. We compare any public IP found against your known public IP to flag a leak.
What are mDNS candidates?: Modern browsers replace raw local IPs in host candidates with randomized .local hostnames (mDNS) to protect your privacy. When you see an mDNS candidate, your local IP is being hidden - that's the secure, expected behaviour.
How do I prevent WebRTC leaks?: Use a VPN or browser extension that disables or proxies WebRTC, turn off WebRTC in your browser's settings or via an extension, or use a browser that routes WebRTC through the VPN tunnel. Re-run this test afterwards to confirm your real IP is no longer exposed.