reply_markup = {
  "inline_keyboard": [
    [
      {
        "text": "Read more.",
        "url": "https://page.toolman.xyz/"
      }
    ]
  ]
}

'https://api.telegram.org/bot<TOKEN>/sendMessage?chat_id=@toolmanxyz&parse_mode=HTML&text=' . $txt . '&reply_markup={"inline_keyboard":[[{"text":"Read more.","url":"https://share.toolman.xyz/' . $art->id . '"}]]}'

https://hackmd.io/@truckski/HkgaMUc24?type=view