Quick overview
This workflow runs daily and checks each site listed in Google Sheets for domain expiry (RDAP), SSL certificate expiry (nslookup.io), and HTTP uptime, then sends priority-based tiered alerts and a weekly Telegram health summary.
How it works
- Runs every day at 7:00 AM on a schedule.
- Fetches the IANA RDAP bootstrap file and builds a TLD-to-RDAP-server map for resolving the correct registry lookup endpoint.
- Reads the list of monitored sites from a Google Sheets tab and processes them one by one.
- For each site, looks up domain expiry via RDAP, checks SSL certificate days-until-expiry via nslookup.io, and performs an HTTP request to determine uptime status.
- Calculates the highest alert tier across domain, SSL, and uptime results and applies a minimum alert threshold based on the site’s priority.
- When an alert is required, sends a formatted Telegram message and appends the incident details to a Google Sheets history tab.
- After all sites are checked, sends a weekly Telegram digest on the configured weekday when weekly summaries are enabled.
Setup
- Create Telegram bot credentials in n8n using a BotFather token and set the target chat ID for where alerts should be delivered.
- Connect Google Sheets OAuth2 credentials and create a spreadsheet with
sites and history tabs using the expected column headers.
- Fill in the Configuration values, including the Google Sheet ID, sites/history sheet names, Telegram chat ID, and whether weekly digests are enabled (and which weekday to send them).