Free SSL Certificate Checker & TLS Security Scanner

Test your SSL certificate online with our free advanced SSL/TLS checker. Get instant A+ security grades, HTTP/2 & HTTP/3 testing, cipher analysis, vulnerability scanning, and enterprise-level certificate validation in seconds.

No credit card required • Instant results

Certificate Validation

Verify SSL certificate validity, check issuer, certificate chain, and Subject Alternative Names (SAN)

HTTP/2 & HTTP/3

Detect HTTP/2 and HTTP/3 (QUIC) support for next-gen web performance

TLS & Cipher Analysis

Complete TLS version testing (1.0-1.3) and cipher suite security analysis

Vulnerability Scanner

Detects POODLE, BEAST, FREAK, LOGJAM, and other SSL/TLS vulnerabilities

A+ Security Grade

SSL Labs-style grading based on TLS version, cipher strength, and security features

Key Size Analysis

Detailed RSA/ECDSA key information with strength assessment (2048, 4096-bit)

Advanced Features

OCSP stapling, session resumption, and certificate chain validation

Comprehensive SSL/TLS Security Testing - What We Check

Certificate & Chain Analysis

  • Certificate validity and expiration dates
  • Issuing Certificate Authority (CA)
  • Complete certificate chain validation
  • Subject Alternative Names (SAN) - multi-domain support
  • Serial numbers and certificate metadata

TLS Protocol & Version Testing

  • TLS 1.0, 1.1, 1.2, and 1.3 support detection
  • Preferred TLS version identification
  • Deprecated protocol warnings (TLS 1.0/1.1)
  • SSL/TLS protocol security grading

HTTP Protocol Support

  • HTTP/3 (QUIC) - Next-generation protocol detection
  • HTTP/2 - Modern protocol support testing
  • Performance optimization recommendations
  • Alt-Svc header analysis

Cipher Suite & Key Analysis

  • Active cipher suite identification
  • Cipher security level (strong/adequate/weak)
  • RSA/ECDSA key algorithm detection
  • Key size validation (2048, 4096-bit RSA; P-256, P-384 ECDSA)
  • Weak cipher pattern detection (DES, RC4, 3DES, etc.)

Vulnerability Scanning

  • POODLE - SSLv3 vulnerability
  • BEAST - TLS 1.0 cipher weakness
  • FREAK - Export cipher vulnerability
  • LOGJAM - Weak Diffie-Hellman parameters
  • HEARTBLEED detection framework
  • CRIME detection framework

Advanced TLS Features

  • OCSP stapling support detection
  • Session resumption (Session ID & Ticket)
  • HSTS (HTTP Strict Transport Security)
  • Certificate transparency logs
  • Enterprise-grade A+ to F grading

Enterprise-Grade SSL/TLS Testing

Our advanced SSL checker performs the same comprehensive tests as enterprise security tools, giving you professional-grade insights into your website's encryption and security posture.

SSL Labs-style grading
6+ vulnerability tests
HTTP/3 detection
Instant results

Frequently Asked Questions About SSL Certificate Testing

What is an SSL certificate checker?

An SSL certificate checker is a free online tool that validates and tests your website's SSL/TLS certificate. It checks certificate validity, expiration dates, issuer information, encryption strength, TLS versions, HTTP/2 and HTTP/3 support, cipher suites, and security vulnerabilities. Our checker provides enterprise-grade analysis with instant A+ to F security grading.

How do I check if my SSL certificate is valid?

Simply enter your website URL in the checker above and click "Check SSL Certificate". Our tool instantly verifies your certificate's validity, checks expiration dates, validates the certificate chain, tests TLS protocol versions (1.0 through 1.3), analyzes cipher suites, and scans for vulnerabilities like POODLE, BEAST, and FREAK. Results are displayed in seconds with a comprehensive security grade.

What does the SSL security grade mean?

Our SSL checker provides SSL Labs-style security grades from A+ to F based on multiple factors: certificate validity, TLS version support, cipher suite strength, key size (RSA 2048/4096-bit or ECDSA P-256/P-384), known vulnerabilities, and modern security features like OCSP stapling and session resumption. An A+ grade indicates excellent security with no known vulnerabilities and strong encryption.

Does this SSL checker test HTTP/2 and HTTP/3?

Yes! Our advanced SSL/TLS checker tests both HTTP/2 and HTTP/3 (QUIC) protocol support in addition to SSL certificate validation. HTTP/2 and HTTP/3 are modern protocols that significantly improve website performance and security. The checker detects protocol support through ALPN negotiation and Alt-Svc headers, helping you optimize your site's speed and security.

What SSL vulnerabilities does this tool detect?

Our SSL vulnerability scanner detects 6+ critical security issues including: POODLE (SSLv3 vulnerability), BEAST (TLS 1.0 weakness), FREAK (export cipher vulnerability), LOGJAM (weak Diffie-Hellman), HEARTBLEED, and CRIME. It also checks for weak ciphers (DES, RC4, 3DES), deprecated TLS versions (1.0/1.1), inadequate key sizes, and missing security features. All vulnerabilities are clearly highlighted in the results.

Is this SSL checker really free?

Yes, our SSL certificate checker is completely free to use with no registration required. You get instant access to enterprise-grade SSL/TLS testing including certificate validation, TLS version detection, HTTP/2 & HTTP/3 testing, cipher analysis, vulnerability scanning, and A+ security grading. For even more comprehensive website security scanning including malware detection, security headers, and port scanning, check out our full security scan below.

Want the Complete Picture?

FREE

This SSL Certificate Check is great for a quick check, but our Full Security Scan gives you a comprehensive security audit in one go.