I'm not sure. The GFW is rather tricky and is known to do DPI.
For now, yes we are communicating moves in exactly the way you described EventSource! Eg:
{
"fen": "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1",
"status": "active",
"turn": "b",
"white_ready": true,
"black_ready": true,
"spectators": 1,
"in_check": false,
"last_move": "e2e4",
"game_over": false,
"available_colors": [],
"reservations": {
"white": {"reserved": true, "expires_in": 0},
"black": {"reserved": true, "expires_in": 0}
}
}