Question 1

Is anything sent to your server?

Accepted Answer

Almost nothing. Every check runs in your browser. The only request is one call to our own IP endpoint so the page can compare your browser timezone and language against your IP location. Nothing about your browser is stored.

Question 2

What does the WebRTC check actually test?

Accepted Answer

It asks your browser for its own network candidates. Modern browsers hide your private LAN address behind an mDNS name ending in .local — if you see that, WebRTC is not leaking. Raw 192.168.x.x or 10.x.x.x addresses mean it is.

Question 3

Why does comparing the public IP need a button?

Accepted Answer

That step has to send a packet to a public STUN server, which is the only part of this tool that talks to a third party. It is opt-in so nothing leaves your device unless you ask for it.

Question 4

A timezone or language mismatch — is that bad?

Accepted Answer

Not by itself. It just means your browser settings do not match the country your IP is in, which is normal if you use a VPN or travel. It is the signal sites use to guess you are on a VPN.