LAN Speed
Peer-to-peer throughput test over WebRTC. No internet, no server — copy a short code between two devices on the same network.
Pick a role
Open this page on two devices on the same Wi-Fi / LAN. One hosts, the other joins.
Host
Join
Connection
Speed test
Measures round-trip time, then a 6 s send burst in each direction.
How it works
Both devices create an RTCPeerConnection with no ICE servers, so only host (LAN) candidates are gathered. The two pages exchange a base64-encoded SDP offer and answer manually (e.g. by typing, AirDrop, KDE Connect, or a chat app). Once connected, a single ordered RTCDataChannel carries small JSON control messages and 16 KB binary chunks for the throughput test. Backpressure is handled via bufferedAmountLowThreshold. Nothing leaves your LAN.
If a device's browser uses mDNS-obfuscated host candidates (most do), both devices need to be able to resolve .local hostnames on the same subnet — usually fine on home / office Wi-Fi, but corporate guest networks with client isolation will block the connection.