SSL Certificate Checker

Verify SSL/TLS certificate validity, expiry, and issuer for any domain

Your input never leaves your browser — all processing happens client-side.

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Do not include https:// — just the domain name

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Free Online SSL Certificate Checker and Validator

SSL/TLS certificates authenticate websites and encrypt data in transit. This tool uses a public SSL metadata API to retrieve certificate details for any domain — validity period, issuer, certificate authority, and whether the certificate is currently valid.

What is SSL Certificate Checker?

SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are cryptographic protocols that secure communications over the internet. A digital certificate binds a domain name to a public key using a Certificate Authority's (CA) digital signature. When you connect to an HTTPS website, your browser verifies this certificate chain to confirm the server's identity and establish an encrypted connection.

How to Use This Tool

  1. 1Enter a domain name (e.g., example.com or sub.example.com).
  2. 2Click 'Check SSL' to query certificate details.
  3. 3Review validity dates — check if the certificate is current and when it expires.
  4. 4Inspect the issuer and CA chain.
  5. 5Green indicates a valid certificate; red indicates expired or invalid.

Use Cases

  • ▸Monitoring SSL expiry before it causes a site outage.
  • ▸Verifying a newly installed certificate is working correctly.
  • ▸Security auditing — checking certificate authorities and configurations.
  • ▸Debugging mixed content or HTTPS issues.

Is It Safe to Use?

SSL certificate metadata is public information — it is transmitted to every browser that connects to a site. This tool queries a public API to retrieve that same metadata. The domain name you enter is sent to the API, but no sensitive data is involved — certificate information is already publicly visible.

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Frequently Asked Questions

Why is SSL/TLS important?

SSL/TLS encrypts data in transit between the browser and server, preventing eavesdropping and man-in-the-middle attacks. It also authenticates the server identity, ensuring you're connecting to the real website. Modern browsers mark sites without HTTPS as 'Not Secure'.

What does certificate expiry mean?

SSL certificates have a validity period (typically 90 days to 1 year). After expiry, browsers display a security warning and refuse to connect by default. Certificate expiry is a common cause of website outages and should be monitored proactively.

What is a certificate chain?

TLS uses a chain of trust: your domain certificate is signed by an intermediate certificate authority (CA), which is signed by a root CA trusted by browsers. If any link in this chain is broken or untrusted, the connection will fail.

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