How to Check SSL Certificate Online Free [2026]

Enterno.io Editorial Team

How to Check a Site's SSL Certificate Online

By Anatoly Oshmanovsky · Updated Apr 17, 2026

TL;DR:

To check a site's SSL certificate: open the Enterno.io SSL checker, enter a domain (example.com), click "Check". In 1-2 seconds you get a full picture — expiry, issuer, chain, TLS protocols, grade A-F. Free, no signup.

Try it now — free →

Step-by-step guide

Open the SSL checker. Go to enterno.io/en/ssl. Free tool, no signup.
Enter a domain. In the Domain field, enter the site address without https:// (e.g., enterno.io). IDN domains and ports (:8443) supported.
Click "Check". Results appear in 1-2 seconds. If the certificate is valid, you'll see a grade A-F and details.
Review the results. Look for: (1) expiry — should be > 14 days; (2) complete chain — no missing intermediate; (3) TLS 1.2/1.3 support; (4) grade — A/A+ for production.
Get a 14-day alert. For continuous monitoring, set up SSL monitoring — Enterno.io sends email/Telegram 14 days before expiry.

Open tool →

CertificateExpiry, issuer, domains (SAN)

ChainIntermediate and root CA validation

TLS ProtocolTLS version and cipher suite

VulnerabilitiesHeartbleed, POODLE, weak ciphers

Why teams trust us

TLS 1.3

supported

Full

CA chain check

<2s

result

30/14/7

days-to-expiry alerts

How it works

Enter domain

TLS chain verified

Expiry date & vulnerabilities

What Does the SSL Check Cover?

SSL/TLS is the encryption protocol that protects data between the browser and server. Our tool analyzes the certificate, chain of trust, TLS version, and knownvulnerabilities.

Certificate Details

Issuer, validity period, signature algorithm, covered domains (SAN), and validation type (DV/OV/EV).

Chain of Trust

Full chain verification: from leaf certificate through intermediates to root CA.

TLS Analysis

Protocol version (TLS 1.2/1.3), cipher suites, Perfect Forward Secrecy (PFS) support.

Expiry Alerts

Set up a monitor — get Telegram and email alerts 30/14/7 days before expiration.

DV vs OV vs EV Certificates

DV (Domain Validation)

Confirms domain ownership only
Issued in minutes automatically
Free via Let's Encrypt
Suitable for most websites
Most common certificate type

OV / EV

Organization (OV) or Extended Validation (EV)
Issued in 1-5 business days
Costs $50 to $500/year
For finance, e-commerce, government sites
Increases user trust

Who uses this

DevOps

SSL certificate monitoring

Security

TLS config audit

SEO

HTTPS as ranking factor

E-commerce

customer trust

Common Mistakes

❌

Expired certificateBrowsers block sites with expired SSL. Set up auto-renewal or monitoring.

❌

Incomplete certificate chainWithout intermediate CA, some browsers and bots cannot verify the certificate.

❌

Mixed content on HTTPS siteHTTP resources on an HTTPS page — the browser lock icon disappears, reducing trust.

❌

Using TLS 1.0/1.1Legacy TLS versions have known vulnerabilities. Use TLS 1.2+ or 1.3.

❌

Domain mismatch in certificateThe certificate must cover all site domains, including www and subdomains.

Best Practices

✓

Set up auto-renewalLet's Encrypt + certbot with cron — certificate renews automatically every 60-90 days.

✓

Enable HSTSStrict-Transport-Security header forces browsers to always use HTTPS.

✓

Use TLS 1.3TLS 1.3 is faster (1-RTT handshake) and safer — legacy ciphers removed.

✓

Monitor expiration datesCreate a monitor on Enterno.io — get notified well before expiration.

✓

Verify chain after renewalAfter certificate renewal, confirm that intermediate certificates are installed.

Get more with a free account

SSL certificate monitoring, check history and alerts 30 days before expiry.

Learn more

How-to

Glossary

Research

TLS Cipher Suites 2026: Distribution Report

Errors

Alternatives

Frequently Asked Questions

Is signup required?

For a quick check (1-2 requests/min) — no. For continuous monitoring — free account. No credit card.

Is this free?

Yes. Enterno.io Scout is a forever-free plan with 5 monitors. All basic tools without signup.