SSL Certificate Checker
Verify SSL/TLS certificate validity, expiry date, issuer, and protocol for any domain. Catch expiring certificates before they take your site down.
What Is an SSL/TLS Certificate?
An SSL/TLS certificate is a cryptographic document that enables encrypted communication between a web server and a browser. It serves two purposes: verifying the server's identity (you're really talking to example.com, not an impersonator) and encrypting the data in transit.
TLS (Transport Layer Security) is the modern protocol — SSL (Secure Sockets Layer) has been deprecated since 2015. But "SSL certificate" remains the common term. When your browser shows the padlock icon, it means TLS is active and the certificate is valid.
Certificates are issued by Certificate Authorities (CAs) like Let's Encrypt, DigiCert, and Sectigo. Let's Encrypt provides free certificates and is the most widely used CA, powering over 300 million websites. Commercial CAs offer extended validation and warranty coverage.
Why HTTPS Matters
Security
Without HTTPS, anyone on the same network can read or modify the data between your users and your server. Passwords, API keys, personal data — all sent in plain text. HTTPS encrypts everything.
SEO & Rankings
Google has used HTTPS as a ranking signal since 2014. Chrome marks HTTP sites as "Not Secure." Modern browsers restrict features like geolocation, service workers, and HTTP/2 to HTTPS-only contexts.
Trust & Compliance
PCI DSS requires HTTPS for any site handling payment data. HIPAA requires encryption in transit for health data. Even if compliance doesn't apply to you, users trust sites with the padlock icon more.
API Reliability
An expired SSL certificate is the most common cause of preventable API outages. Certificate monitoring with automated alerts ensures you renew before expiry. PulseAPI checks your certs every 6 hours.
Frequently Asked Questions
Never Let a Certificate Expire Again
PulseAPI monitors your SSL certificates 24/7 and alerts you before they expire. Get notified 30, 14, and 7 days in advance — by email, Slack, or webhook.