Wildcard SSL Certificate (Wildcard Certificate)
Why Wildcard Certificate Matters
Wildcard certificates simplify management when you run multiple subdomains. Instead of obtaining and renewing separate certificates for each subdomain, a single wildcard covers them all. This reduces administrative overhead and the risk of individual certificates expiring unnoticed.
However, wildcards carry a security tradeoff. If the wildcard certificate's private key is compromised, every subdomain is affected simultaneously. For this reason, some organizations prefer individual certificates for critical services (like payments or authentication) while using wildcards for less sensitive subdomains. The principle of least privilege suggests limiting the blast radius of a key compromise.
Wildcard certificates only cover one level of subdomain. A certificate for .example.com covers blog.example.com but not blog.staging.example.com. For multi-level subdomains, you would need either a separate wildcard (.staging.example.com) or SAN certificates listing each specific subdomain. Let's Encrypt supports wildcard certificates, but they require DNS-01 challenge validation instead of the simpler HTTP-01 challenge.
How to Check
An SSL checker will show whether a wildcard certificate is in use and which subdomains it covers. Check that the common name or SAN field shows *.yourdomain.com. Verify the certificate covers both the wildcard and the apex domain if you need both.
Check SSL Certificate