Why is PHP saying "undefined index request"? The json format looks completely correct to me.

let json = JSON.stringify(
  { request:  "getUser" },
  { username: "test" }
);

const response = await axios.post('http://localhost/projects/serverFiles/index.php', json);

My PHP

<?php
    ini_set("log_errors", 1);

    header('Access-Control-Allow-Origin: *');
    header('Content-Type: application/json');
    
    echo print_r($_POST["request"]);
?>