Protego

SSL Certificate Checker

Check SSL/TLS certificate details, validity, expiration, and security configuration for any domain. Monitor multiple domains and get alerts before certificates expire.

SSL/TLS Security Best Practices

✓ Use TLS 1.3

TLS 1.3 is the latest and most secure version. It offers faster handshakes and removes outdated cryptographic algorithms.

✓ Enable HSTS

HTTP Strict Transport Security forces browsers to use HTTPS, preventing protocol downgrade attacks.

✓ Monitor Expiration

Set up automated monitoring to alert you before certificates expire. Consider using auto-renewal with Let's Encrypt.

✓ Use Strong Ciphers

Configure your server to use only strong cipher suites like AES-256-GCM and disable weak ciphers.

Best SSL Certificate Providers Compared (2026)

Choosing the right SSL certificate depends on your needs. Here's how the top providers compare for security, pricing, and features.

ProviderTypePriceValidationWarrantyBest For
Cloudflare
Universal SSL
Free$0/yrDVNoneVisit
Let's Encrypt
Open Source CA
Free$0/yrDVNoneVisit
DigiCert
Recommended
Paid$268/yrOV / EV$1.75MVisit
Sectigo
Formerly Comodo
Paid$70/yrDV / OV / EV$500KVisit
GoDaddy
Bundled Hosting
Paid$63/yrDV / OV / EV$100KVisit
GlobalSign
Enterprise CA
Paid$249/yrOV / EV$1.5MVisit

DV = Domain Validation (basic encryption) | OV = Organization Validation (verified company) | EV = Extended Validation (highest trust, green bar). For e-commerce and sites handling personal data, we recommend OV or EV certificates with warranty coverage.

Common SSL Certificate Issues & How to Fix Them

SSL Certificate Expired

An expired SSL certificate causes browsers to display a "Your connection is not private" warning, immediately driving visitors away.

How to fix:

  • 1. Renew your certificate through your SSL provider or hosting panel
  • 2. Install the renewed certificate on your web server
  • 3. Set up auto-renewal (Let's Encrypt certbot supports this)
  • 4. Use our monitor feature above to track expiration dates

Mixed Content Warnings

Mixed content occurs when your HTTPS page loads images, scripts, or CSS over insecure HTTP. This degrades your SSL grade and triggers browser warnings.

How to fix:

  • 1. Update all resource URLs from http:// to https://
  • 2. Use protocol-relative URLs (//example.com/image.png)
  • 3. Add a Content-Security-Policy: upgrade-insecure-requests header
  • 4. Use a CDN like Cloudflare to automatically rewrite URLs

Certificate Name Mismatch

This happens when your SSL certificate was issued for a different domain than the one visitors are accessing (e.g., certificate for www.example.com but site served at example.com).

How to fix:

  • 1. Reissue the certificate with all domain variants as SANs
  • 2. Use a wildcard certificate (*.example.com) for subdomains
  • 3. Set up proper redirects from non-matching domains

Weak Cipher Suites / Outdated TLS

Using TLS 1.0/1.1 or weak ciphers (RC4, DES, 3DES) makes your site vulnerable to attacks like BEAST, POODLE, and SWEET32.

How to fix:

  • 1. Disable TLS 1.0 and TLS 1.1 on your server
  • 2. Enable TLS 1.2 and TLS 1.3 only
  • 3. Configure cipher preference: AES-256-GCM, CHACHA20-POLY1305
  • 4. Use our SSL Checker above to verify your configuration

SSL Monitoring & Website Security Tools

For production environments, pair our free checker with a dedicated monitoring solution to get alerts before certificates expire.

UptimeRobot

Free tier monitors up to 50 websites with SSL expiry alerts. 5-minute check intervals.

Free plan availableLearn more

Datadog

Enterprise-grade monitoring with SSL certificate checks, synthetic testing, and real-time alerting.

From $15/host/moLearn more

Sucuri

Website security platform with SSL monitoring, malware scanning, WAF, and DDoS protection included.

From $199/yrLearn more

Frequently Asked Questions

What is an SSL certificate?
An SSL (Secure Sockets Layer) certificate is a digital certificate that authenticates a website's identity and enables an encrypted connection between a web browser and server. Modern certificates use TLS (Transport Layer Security), which is the successor to SSL.
What is the difference between free and paid SSL certificates?
Free SSL certificates (like Let's Encrypt and Cloudflare) provide basic domain validation (DV) encryption. Paid certificates offer organization validation (OV) and extended validation (EV) with company name verification, warranty coverage up to $1.75M, wildcard domain support, and dedicated support. For e-commerce or sites handling sensitive data, paid certificates provide higher trust.
How do I fix an expired SSL certificate?
Log into your SSL provider or hosting panel, renew or reissue the certificate, install the new certificate on your server, and verify using our SSL Checker tool above. If you use Let's Encrypt, run "certbot renew" in your terminal. Managed hosting platforms like Vercel and Cloudflare handle auto-renewal for you.
What does the SSL grade (A+ to F) mean?
The SSL grade indicates overall security strength. A+ means excellent security with modern TLS 1.3, strong ciphers, HSTS enabled, and no vulnerabilities. Lower grades indicate issues like weak cipher suites (grade B), outdated TLS versions (grade C), or expired/invalid certificates (grade F).
Do I need SSL for SEO ranking?
Yes. Google confirmed HTTPS as a ranking signal in 2014 and has strengthened this over time. Sites without SSL are marked as "Not Secure" in Chrome, increasing bounce rates. All major search engines prefer HTTPS sites, making SSL essential for SEO.
What is mixed content and how does it affect my SSL?
Mixed content occurs when an HTTPS page loads resources (images, scripts, CSS) over insecure HTTP. This triggers browser warnings, degrades your SSL grade, and can block resources entirely. Fix it by updating all URLs to HTTPS or using a Content-Security-Policy header.
How often should I check my SSL certificate?
Monitor SSL certificates continuously for production sites. At minimum, check monthly and set up alerts for 30 days before expiration. Use our Monitor tab above to track multiple domains. For enterprise environments, use automated monitoring tools like UptimeRobot or Datadog.
What is a wildcard SSL certificate?
A wildcard SSL certificate secures a domain and all its first-level subdomains with a single certificate. For example, *.example.com covers shop.example.com, blog.example.com, and api.example.com. This is more cost-effective than purchasing individual certificates for each subdomain.

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