SSL Lookup

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About the SSL Lookup

SSL Lookup inspects the TLS certificate a domain currently presents and shows issuer, validity dates, subject alternative names and the public key algorithm.

How to use it

Enter the hostname.
The tool queries the certificate and decodes its fields.
Review the chain.

When to use it

Confirming that a renewal completed.
Auditing which subdomains a wildcard cert covers.
Verifying that intermediate certificates are correctly installed.

What is an SSL/TLS Certificate Lookup?

An SSL lookup, also called a TLS certificate checker, connects to a domain's secure endpoint and inspects the digital certificate it presents. That certificate is what encrypts the connection between a browser and a server, and it is issued to a specific hostname by a certificate authority. The lookup extracts the issuer, the subject, the exact dates the certificate is valid from and until, the list of hostnames it covers (subject alternative names), and the public-key and signature algorithms. This tool does that handshake for you and reports the details in plain language.

How to Use This SSL Lookup Tool

Enter the hostname you want to check (with or without the https:// prefix, for example bagiqo.com or www.example.com) and press the Check button. The tool opens a TLS connection to the standard port and reads the presented certificate, then shows you the issuer, validity window, days remaining before expiry, supported SAN hostnames, and cipher information where available. There is no need to install anything, and you can check as many domains as you like.

Common Use Cases

System administrators set up reminders before a certificate expires — this checker reports the remaining days so you can renew on time and avoid browser warnings. E-commerce and lead-generation site owners verify their certs are valid and correctly cover the www and apex hostnames. Developers confirm that a newly issued or just-renewed certificate has actually been deployed on the live server, and IT auditors document the certificate posture of the domains they operate.

Limitations

This lookup checks the certificate presented on the public network from the checker's vantage point. If a domain uses a CDN or a load balancer that terminates TLS, you see that edge certificate rather than the origin. Certificates served only behind a firewall or on a non-standard port must be checked directly from within that network, and expired or misconfigured certificates can cause the handshake to fail before any details can be read.

Frequently asked questions

Why does it matter if a certificate expires?

When a certificate expires, browsers and apps refuse to trust the connection and show security warnings that drive visitors away and can block API clients. Checking remaining days lets you renew before that happens.

Why does my domain show a different issuer when behind a CDN?

When Cloudflare, a CDN or a load balancer terminates TLS, the certificate you see in a public lookup belongs to that edge provider, not to your origin server. That is expected and normal for proxied sites.

What is the difference between the subject and SAN hostnames?

The subject names the primary hostname the certificate was issued for, while the subject alternative names (SAN) list every hostname the certificate is valid for — for example both www.example.com and example.com. The SAN field is what modern browsers actually validate against.