Planning poker
Estimate together,
reveal at once.
Everyone picks a card, nobody sees anyone else's until the host says so. The hiding happens on the server, which is the only place it means anything.
Nobody can peek
Cards are withheld by the server until the reveal. Open the network tab during a round and there is nothing to find — a hidden vote that ships to every browser is not hidden.
Presence is the connection
The list of people in a room is derived from the open sockets, so closing a laptop removes you and reconnecting puts you back in the same seat.
One link, no account
Rooms are created by visiting them. Nothing to install, nothing to sign up for, nothing to clean up afterwards.