Measures the connection between two browsers directly. Open this link on the other device, or send it to someone else. The two sides connect to each other, not to a server.
On macOS 26 and iOS, this browser asks for Local Network permission as soon as this page opens. The page is getting ready: it has sent nothing anywhere, and no connection to another device has started. Answer yes, because that permission is what lets the two devices find each other on the local network.
Opening the room…
This test moves real data across both devices.
A full run sends up to 953.67 MiB from this device and receives up to 953.67 MiB on it. That is up to 1.86 GiB on each device.
Do not start this test on a metered connection or on a mobile data plan.