$.ajax({
      async: true,
      crossDomain: true,
      crossDomain: true,
      url: "myajaxurl.com/api",
      method: "GET",
      headers: {
         "Authorization": "Basic " + btoa('pubkey-NgfPoF0x0GIo0uA6a792SuBb8TL73I' + ":" + 'key-QJ6W6i1gPBSbMqO21071rdkPV38g0G')
      },
      success: function (data) {
        console.log(data);
      }

});

console.log(data); // this is not working 'data is not defined'