These network tools answer a narrow question about a public host or about this connection. They are free, they do not need an account, and they are not a monitoring service. A check is not stored and it is not written to a log.
Is This Website Down asks Cloudflare to fetch one URL and reports the status and the time it took. HTTP Headers and Redirect Checker read a public response and list the header fields or the hop chain. HTTP Status Codes explains a code you already have. It does not call a site. Port Check opens one TCP port and stops. It is not a scanner, and a timeout is not proof that the port is closed.
DNS Lookup runs in the browser against Cloudflare's public DNS-over-HTTPS resolver. It prints the record you asked for. This DNS lookup does not follow CNAMEs. Whois Lookup asks RDAP for the registrar, the nameservers, and the expiry. SSL Certificate Checker reads the certificate a public host presents and shows the issuer and the days left.
What Is My IP and IP Geolocation describe this connection only. They use the address Cloudflare attaches to the request. They do not look up an address you paste. CIDR Calculator and User-Agent Parser stay on this device. One turns an IPv4 range into a network and a broadcast address. The other splits a user-agent string you paste.
Tools
Read the privacy page for what each check sends.