localhost issued 3 of the 8,208 certificates we observed on popular sites in November 2026.
Days between notBefore and notAfter of the leaf certificate.
On sites using localhost (accent) and all sites (grey).
Issuer organisation names seen in these certificates: localhost (3).
33.3% of the domains using localhost publish a CAA record (all sites: 20.7%). A CAA record names the CAs allowed to issue for the domain; any other CA must refuse.
1 certificate from localhost had already expired when we checked.
Check one yourself:
Source: our own scan of November 2026 (2026-11-11), 9,971 of the top 10,000 domains of the Tranco list Y895G that answered in DNS. Method and data.