JavaScript

params = {
    matrix: [
        [0, 5, 6, 4, 7, 4],
        [5, 0, 5, 4, 6, 5],
        [6, 5, 0, 4, 5, 5],
        [4, 4, 4, 0, 5, 5],
        [7, 6, 5, 5, 0, 4],
        [4, 5, 5, 5, 4, 0]
    ],
    names: ["Action", "Adventure", "Comedy", "Drama", "Fantasy", "Thriller"]
}

var authorizationBasic = window.btoa("api_key:" + your_api_key);

var request = new XMLHttpRequest();
request.open('POST', "https://plotapi.com/chord", true);
request.setRequestHeader('Content-Type', "application/json;charset=UTF-8");
request.setRequestHeader('Authorization', 'Basic ' + authorizationBasic);
request.setRequestHeader('Accept', 'application/json');

request.send(JSON.stringify(params));

request.onreadystatechange = function () {
    if (request.readyState === 4) {
       console.log(request.responseText);
    }
};