Is an API key even needed? This works for me:
let spid;
function preload() {
spid = loadJSON('https://static.api.nexon.co.kr/fifaonline4/latest/spid.json');
}
function setup() {
console.log(spid[0]);
}
Resulting in this output:
Object {id: 101000001, name: "데이비드 시먼"}
id: 101000001
name: "데이비드 시먼"