How to set a key for a button in a telegram bot?

Question

PHP

I am doing this now

$buttons = [
  'resize_keyboard' => true,
  'keyboard' => [
    ['Кнопка 1', 'Кнопка 2'],
  ],
];

$content = array(
    'chat_id' => $data['message']['from']['id'],
    'reply_markup' => json_encode($buttons),
    'text' => "Test"
);


message_to_telegram($content);

function message_to_telegram($array)
{
    $ch = curl_init();
    curl_setopt_array(
        $ch,
        array(
            CURLOPT_URL => 'https://api.telegram.org/botAPI/sendMessage',
            CURLOPT_POST => TRUE,
            CURLOPT_RETURNTRANSFER => TRUE,
            CURLOPT_TIMEOUT => 10,
            CURLOPT_POSTFIELDS => $array,
        )
    );
    curl_exec($ch);
}

But why can't I set a key for the buttons?

$buttons = [
  'resize_keyboard' => true,
  'keyboard' => [
    [ 'btn1' => 'Кнопка 1',   'btn2'  => 'Кнопка 2'],
  ],
];

Answer 1

"Keys" can only be set for the inline keyboard.