Check whether your connection can send and receive UDP traffic, how fast the replies come back, and which public IP address your UDP traffic uses — compared with the IP address used for normal web browsing.
How to run the UDP test
- Open the page — the test starts automatically.
- Wait a few seconds while your browser sends UDP packets to several test servers.
- Check the result: whether UDP works, how many packets were answered, the latency, and the IP your UDP traffic came from.
- Click Run again after changing your network settings to compare.
What is UDP?
UDP (User Datagram Protocol) is one of the two main ways data travels over the internet. Unlike TCP, which is used for most web pages, UDP sends packets without setting up a connection first, which makes it fast and ideal for real-time traffic: online gaming, voice and video calls, live streaming, DNS lookups and modern HTTP/3 (QUIC) connections.
How the UDP test works
Browsers can't open raw UDP sockets, but they can send STUN requests over UDP using WebRTC — the same technology used for video calls. Your browser sends STUN binding requests to our own STUN server and to public STUN servers from Google and Cloudflare. Each server replies over UDP with the public IP address and port it saw the packet come from.
If replies arrive, UDP works on your connection. The number of replies shows packet loss, and the time until the reply arrives gives an approximate round-trip latency.
Why can the UDP IP differ from my IP?
Normal web pages load over TCP, while this test uses UDP. If a VPN, proxy, gateway or firewall handles the two protocols differently, your UDP packets can leave the network from a different public IP than your web traffic — or not at all. When both IPs match, all your traffic uses the same route.
Frequently asked questions
Why does the test say UDP is blocked?
No test server replied over UDP. A firewall, corporate or public Wi-Fi network, VPN setting or browser extension may be blocking UDP or WebRTC. Try another network to compare.
Can I test UDP if WebRTC is disabled?
No. Browsers can only send UDP through WebRTC (and HTTP/3). If WebRTC is disabled in your browser or by an extension, the test can't send UDP packets.
Does this test a specific UDP port on my computer?
No. It checks whether your connection can send UDP to the internet and receive replies, which is what games, calls and streaming need. Incoming ports on your device are not scanned.
Is the latency accurate?
It's an approximation measured in the browser, including a little processing overhead. Use it to compare connections rather than as an exact ping.