UptimeRobot, Better Stack or Pingdom for a UK Retailer Before Peak Trading
UptimeRobot is the cheapest and fastest option for basic up-or-down alerts, while Better Stack and Pingdom both add checkout-flow transaction testing, one through a self-written script billed by the minute and the other configured and bundled into the price. Neither of the two free tiers, from UptimeRobot and Better Stack, is really built for a live storefront during peak trading.