var EmployeesAsJson = [
        {
            __metadata: {
                type: 'SP.Data.EmployeesListItem'
            },
            FirstName: 'User1',
            LastName: 'Test1',
            Email: 'User1.Test1@email.com'
        },
        {
            __metadata: {
                type: 'SP.Data.EmployeesListItem'
            },
            FirstName: 'User2',
            LastName: 'Test2',
            Email: 'User2.Test2@email.com'
        },
        {
             __metadata: {
                 type: 'SP.Data.EmployeesListItem'
             },
             FirstName: 'User3',
             LastName: 'Test3',
             Email: 'User3.Test3@email.com'
         }



    var batchGuid = generateUUID();

    // creating the body
    var batchContents = new Array();
    var changeSetId = generateUUID();

    // get current host
    var temp = document.createElement('a');
    temp.href = _spPageContextInfo.webAbsoluteUrl;
    var host = temp.hostname;

    // for each employee...
    for (var employeeIndex = 0; employeeIndex < employeesAsJson.length; employeeIndex++) {

        var employee = employeesAsJson[employeeIndex];

        // create the request endpoint
        var endpoint = _spPageContextInfo.webAbsoluteUrl
                       + '/_api/web/lists/getbytitle('Employees')'
                       + '/items';

        // create the changeset
        batchContents.push('--changeset_' + changeSetId);
        batchContents.push('Content-Type: application/http');
        batchContents.push('Content-Transfer-Encoding: binary');
        batchContents.push('');
        batchContents.push('POST ' + endpoint + ' HTTP/1.1');
        batchContents.push('Content-Type: application/json;odata=verbose');
        batchContents.push('');
        batchContents.push(JSON.stringify(employee));
        batchContents.push('');
    }
    // END changeset to create data
    batchContents.push('--changeset_' + changeSetId + '--');

    // generate the body of the batch
    var batchBody = batchContents.join('rn');

    // create the request endpoint
    var endpoint = _spPageContextInfo.webAbsoluteUrl
                   + '/_api/$batch';

    // batches need a specific header
    var batchRequestHeader = {
        'X-RequestDigest': jQuery("#__REQUESTDIGEST").val(),
        'Content-Type': 'multipart/mixed; boundary="batch_' + batchGuid + '"'
    };

    // create request
    jQuery.ajax({
        url: endpoint,
        type: 'POST',
        headers: batchRequestHeader,
        data: batchBody,
        success: function (response) {
            alert("Successfully saved a batch request");
        },
        fail: function (error) {
            alert('.. create employee FAIL ', error);
        }
    });