>• ipconfig.is

TLS certificate checker

Inspect an SSL/TLS certificate: validity and days remaining, the chain including missing intermediates, revocation, the TLS versions the server accepts, the key and its fingerprint. Mail ports use STARTTLS.

What it checks

• Validity and days remaining
• Chain, incl. missing intermediates
• Revocation (CRL) and key
• Accepted TLS versions, STARTTLS

The same check from the command line

curl "ipconfig.is/tls?host=github.com"

All tools

• Domain security audit: TLS certificate, chain and versions
• DNS lookup: 20 record types, A to DNAME
• DNS propagation checker: 12 public resolvers worldwide
• TLS certificate checker: Validity and days remaining
• SPF, DKIM and DMARC checker: SPF with the 10-lookup limit
• HTTP redirect checker: Every redirect hop
• Domain WHOIS lookup: Registrar and registration date
• Subnet calculator: Network, broadcast and usable range

Every tool is also a key-free API call: see the API reference.