Free WebRTC tool

ICE candidate inspector

See exactly which ICE candidates your browser gathers, discover your NAT situation, and test your own STUN or TURN server. Everything runs locally in your browser.

// ICE servers to test against

stun.l.google.com stun.cloudflare.com stun1.l.google.com

// Optional: test your own STUN or TURN server

No camera or microphone is used. The tool opens a data-channel-only peer connection, so no permission prompts appear.

host

Local addresses on this device. Modern browsers hide these behind .local mDNS names for privacy.

srflx (STUN)

Your public address as seen by the STUN server. Needed to connect across NAT.

relay (TURN)

Relayed addresses from a TURN server. Only appear if you supplied working TURN credentials.

// Gathered candidates

Type	Protocol	Address	Port	Priority

host

A candidate on one of your device's own network interfaces (Wi-Fi, Ethernet, VPN). Two devices on the same LAN can connect directly using these.

srflx

Server reflexive: your public IP and port as observed by a STUN server. If you see srflx candidates, STUN is working and most peer-to-peer connections will succeed.

relay

A TURN server address that relays your media when a direct path is impossible. Roughly 15 to 20 percent of real-world connections need this.

.local addresses

Browsers replace your private LAN IP with a random name like a1b2.local to stop websites fingerprinting your network. This is normal and expected.

Privacy: this tool talks only to the STUN or TURN servers you select above, which is the same thing any WebRTC call does. Nothing is sent to Sazrika Foundation. Your candidates are displayed on your screen and never leave your browser.

What is an ICE candidate?

When two browsers try to connect with WebRTC, each side gathers a list of possible network paths called ICE candidates. ICE stands for Interactive Connectivity Establishment. Candidates come in three flavours: host candidates from your device's own interfaces, srflx candidates discovered through a STUN server that reveal your public address, and relay candidates allocated on a TURN server for when nothing else works. The two peers exchange these lists and test every pairing until one connects.

Why use this inspector?

If your WebRTC app fails to connect for some users, the ICE candidate list is the first thing to check. No srflx candidates means STUN is blocked or misconfigured. No relay candidates when you expected them means your TURN credentials or firewall rules are wrong. This inspector shows the same data your app sees, without writing a line of code, and it doubles as a free TURN server tester: paste your turn: URL with its username and credential, gather, and see whether relay candidates appear.

More free tools

This inspector is part of Sazrika Foundation. If you also work with SIP, try SIP Ladder for trace analysis or the SIP Lab call simulator.