Free SSL Expiry Checker
Check certificate expiry, TLS protocol, issuer, and HSTS. No login required.
Tip: you can paste a full URL like https://example.com.
Get email alerts before it expires
Turn this into a monitor and get notified if your SSL certificate is about to expire.
Create an AlertsDown monitorWhat this SSL certificate checker tests
This free SSL checker helps you validate your website security configuration in seconds. Enter any domain to inspect certificate expiration, TLS protocol support, and HSTS response headers. If your SSL certificate is near expiry, you can create an uptime monitor and receive alerts before visitors see browser security warnings.
- SSL certificate expiry date and remaining validity period
- Certificate issuer and protocol-level TLS information
- HSTS header detection for stricter HTTPS protection
- Raw JSON output for debugging and audit workflows
Why SSL expiry monitoring matters
An expired TLS/SSL certificate can break checkout pages, APIs, login flows, and search visibility. Modern browsers block or warn users when a certificate is invalid, which can reduce conversions and trust immediately. Continuous certificate monitoring prevents downtime caused by missed renewals and keeps your HTTPS setup compliant.
If you manage multiple domains, combine this SSL test with AlertsDown monitors to get early warning emails before expiry. This gives your team time to renew certificates and avoid incidents.
How to check SSL certificate expiration
- Enter a hostname (for example:
example.com) or paste a full URL. - Click Check SSL to run an instant certificate and TLS lookup.
- Review days until expiry, protocol, issuer details, and HSTS status.
- Create a monitor to get automatic reminders before certificate expiration.
SSL checker FAQ
Is this SSL checker free?
Yes. You can run unlimited manual SSL checks here without creating an account.
Can I check both domains and full URLs?
Yes. You can enter a hostname like example.com or a full URL like https://example.com/path.
What happens when a certificate expires?
Browsers and clients can reject the connection or show security warnings, causing lost traffic and failed API requests.
How do I get alerts before SSL expiration?
Create an AlertsDown monitor and we'll notify you before expiration so you can renew your certificate in time.