Yahoo! JAPAN Ads Script | Developer Center

function sendSlackMessage(){
  UrlFetchApp.fetch('http://',
  {
    method: 'POST',
    contentType: 'application/json',
    payload: {
      'text': `
        Hello, world.
        http://yahoo.co.jp/
        :cat:`, //specify stamps in English
      icon_url: 'https://xxx.com/icon_400x400.jpg'
    }
  });
}