Who this is for: anyone running a site or service who wants to know automatically if it's reachable, without paying for a separate uptime monitoring service.
Every 5 minutes n8n makes an HTTP request to your site and checks the response code. If it's not 200, the workflow takes the "offline" branch; otherwise it takes the "online" branch. From there you can wire up any notification (email, Telegram, Slack) — the next guide shows how to do it with Telegram without spamming you.
The HTTP Request node is set with neverError: true, so even a 4xx/5xx response doesn't stop the workflow: it still reaches the IF node, which compares statusCode against 200.
This guide stops at the check. For the automatic Telegram notification (only when status changes, not on every check) see: Get a Telegram alert when an endpoint goes down.