Chain integrity
Validates that the root, intermediates, and leaf form an unbroken trust path back to a CA every browser actually trusts.
SSL Certificate Checker
Validates your TLS certificate: chain integrity, expiry date, and negotiated protocol version. Warns when expiry is under 30 days away or the server negotiates deprecated TLS 1.0/1.1.
Instant audit. No account required.
What the SSL Certificate audit checks
Three checks, one verdict. Each tile is a primitive your AI agent can read alongside the full JSON payload.
Expiry window
Counts the days until expiration and flags renewals due in the next 30 - early enough for an auto-renewal cron to land without an incident.
TLS protocol
Reports the negotiated TLS version and warns when the server still accepts deprecated TLS 1.0 or 1.1 downgrade paths.
UpMonitor's SSL Certificate Checker verifies your website's SSL/TLS certificate validity, expiration date, cipher suite strength, and certificate chain integrity. It checks from multiple global regions to detect configuration inconsistencies. Results are delivered in under 3 seconds. Free to use - no signup or login required.
Instantly validate the SSL/TLS security of any website - no account required.
ℹ️
An SSL/TLS certificate (Secure Sockets Layer / Transport Layer Security) is a digital certificate that authenticates a website's identity and enables an encrypted connection between a user's browser and your server. It's what puts the padlock icon in the browser address bar and changes http:// to https://.
Without a valid SSL certificate, modern browsers display aggressive security warnings to your visitors - causing lost traffic, damaged trust, and potential SEO penalties.
What Our SSL Checker Validates
Our free SSL checker performs a comprehensive certificate audit in seconds:
✅ Certificate Validity
Confirms the certificate is currently valid and has not expired. We show the exact expiry date so you know how much time you have.
✅ Expiry Date & Early Warning
We flag certificates expiring within 30 days as a warning - giving you time to renew before browsers flag your site to users.
✅ Certificate Chain
Validates that the complete trust chain (root CA → intermediate → leaf certificate) is correctly configured. Broken chains are a common cause of SSL errors on some devices.
What is the Difference between DV, OV, and EV SSL?
The difference between Domain Validated (DV), Organization Validated (OV), and Extended Validation (EV) SSL certificates lies in the level of identity verification performed by the Certificate Authority. DV confirms domain ownership, OV verifies basic company registration, and EV requires rigorous legal and physical identity checks.
⚠️
Broken certificate chains are one of the most common causes of "Insecure Connection" errors on mobile devices and older operating systems, even if the certificate works fine on your desktop browser.
Why SSL Certificate Health Matters
| Risk | Impact |
|---|---|
| Expired certificate | Immediate browser blockage - visitors see "Your connection is not private" |
| Missing certificate | No HTTPS, lower search ranking, browser warnings |
| Broken chain | SSL errors on mobile/embedded devices |
| Weak protocol (TLS 1.0) | Vulnerability to POODLE, BEAST attacks |
| Wrong domain | NET::ERR_CERT_COMMON_NAME_INVALID browser error |
Common SSL Errors & How to Fix Them
Certificate Expired
Renew your certificate with your Certificate Authority (CA) or hosting provider. Most modern hosts offer Let's Encrypt free auto-renewal via Certbot or ACME protocol.
💡
Always enable Auto-Renewal with your provider to avoid manual renewal headaches and potential downtime.
Broken Certificate Chain
Ensure your server is configured to serve the intermediate CA certificate(s) alongside the leaf certificate. Check your web server's SSL configuration (ssl_certificate in Nginx, SSLCertificateChainFile in Apache).
Frequently Asked Questions
Why is my SSL certificate showing as "Insecure" on mobile?
This is usually caused by a broken certificate chain. While desktop browsers often cache intermediate certificates, mobile browsers are stricter and require the full chain to be served by your web server.
Does a free SSL certificate provide less security?
No. Certificates from providers like Let's Encrypt provide the same level of industry-standard encryption as paid certificates. The main difference is the validation level (DV vs EV) and the lack of a warranty or customer support.
How often should I check my SSL certificate?
For production websites, you should monitor your SSL certificate continuously. UpMonitor's automated system checks your certificate validity every few hours and alerts you 30 days before it expires.
What is the difference between SSL and TLS?
TLS (Transport Layer Security) is the modern, secure successor to SSL (Secure Sockets Layer). Although everyone still uses the term "SSL," modern websites actually use TLS 1.2 or 1.3 to encrypt connections.
Set Up Continuous SSL Monitoring
The free checker above is great for a one-time audit, but SSL certificates expire - and you want to know before your visitors do.
With a UpMonitor account, you can:
- ✅ Monitor your SSL certificate 24/7
- ✅ Receive email alerts 30 days before expiry
- ✅ Track certificate changes over time
- ✅ Get instant alerts if your certificate becomes invalid
Also useful for this stack
Pair the audit you just ran with these checkers - the failure modes tend to travel together.
DNSSEC Status
Queries DS and DNSKEY records via validating DNS-over-HTTPS resolvers (Cloudflare, Google). Returns success when either record is present - signing-chain validation happens at the resolver.
Security Headers
Checks for seven key security headers: HSTS, CSP, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, Permissions-Policy, and Cross-Origin-Opener-Policy. Also performs a deep-dive on HSTS quality.
Liveness & Routing
Consolidated liveness audit: follows redirect chains, verifies secure HTTPS upgrades, measures response timing, and captures final headers.
Stop running this audit by hand.
Schedule SSL Certificate every minute from 12 regions. Get an AI-drafted remediation prompt the moment a check fails - delivered to your inbox, Slack, or MCP-connected agent.