How to Use the SSL Certificate Lookup Tool
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1
Enter a domain name (e.g. cloudflare.com).
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2
Click Check SSL to query public Certificate Transparency (CT) logs.
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3
Inspect certificate authority (CA), issue date, expiration date, and SAN hostnames.
Practical Example & Use Case
Common Real-World Scenario
Checking whether a newly issued Let's Encrypt or DigiCert SSL certificate covers all your wildcard subdomains.
Technical Notes & Limitations
Browser Engine Architecture
Queries public crt.sh certificate transparency logs with zero client data retention.
Frequently Asked Questions
What are SAN hostnames in SSL?
Subject Alternative Names (SANs) allow a single SSL certificate to secure multiple distinct domains and subdomains.