Phishing campaigns start with a domain that looks like yours: one letter swapped, a hyphen added, a lookalike character. Every one of those domains leaves a public trace in certificate transparency logs. Search those logs for your brand in 30 seconds. No signup, nothing installed.
Search certificate transparency logs. Open crt.sh and search for certificates containing your brand name:
https://crt.sh/?q=%25yourbrand%25
(replace "yourbrand" with your brand or domain name, no spaces)
Scan the results for anything you don't recognize — especially domains with swapped letters, extra hyphens, or odd TLDs.
Check the classic typos by hand. The most-abused tricks, using example brand "acme":
acme.com → acme-login.com, acme-secure.com (hyphen tricks)
acme.com → acrne.com, acem.com (letter swaps / drops)
acme.com → acme.net, acme.io, acme.co (TLD swaps)
acme.com → аcme.com (lookalike Unicode chars)
Search crt.sh for each variant the same way as step 1.
crt.sh is a free public log operated for the security community. A domain having a certificate doesn't prove malice — but a lookalike you didn't register deserves a look.
This page showed you the manual check. DomainGuard automates it — watching certificate transparency logs and new registrations for lookalikes and alerting you the moment one appears.