The easiest way to send basic HTTP POST or GET requests using PHP

The easiest way to send basic HTTP POST or GET requests is using PHP’s built in file_get_contents() function in conjunction with HTTP context options:

$data = http_build_query(
    array(
        'firstKey' => 'firstValue',
        'secondKey' => 'secondValue',
        'thirdKey' => 'thirdValue'
    )
);

$options = array('http' =>
    array(
        'method'  => 'POST',
        'header'  => 'Content-type: application/x-www-form-urlencoded',
        'content' => $data
    )
);

$context = stream_context_create($options);

$result = file_get_contents('https://httpbin.org/post', false, $context);

Further reading:

file_get_contents
HTTP context options