The free online uptime monitoring service with an App available for iOS and Android (https://uptimerobot.com). With the Free Plan, you can monitor up to 50 URLs, check for the content of a website (using the keyword monitor), ping your server or monitor your ports in 5-minute intervals. You can create a status page to showcase your uptime. SMS or Call alerts can be bought anytime. Receive notifications via email, phone call, SMS, or integrations like Microsoft Teams, Telegram, Slack, Twitter, Zapier, Pagerduty, Splunk On-Call, Pushbullet, Webhooks, Google Chat, or Pushover. Upgrade to Pro to get more monitors, 1-minute intervals, unlimited status pages that you can customize, share announcements on your status page to which your customers can subscribe and receive them via email. With the Pro Plan, you can monitor SSL certificates or use the Heartbeat monitor to keep an eye on your cron jobs. Adjust and manage your monitoring with maintenance windows or advanced notifications, to avoid getting alerts during maintenance, or to receive notifications after a certain time of downtime.