SSL Certificate Checker
Comprehensive SSL/TLS certificate validation covering expiration monitoring, certificate chain verification, cipher suite security, protocol compliance, and HSTS implementation. Ensure your HTTPS is actually secure.
Why SSL Certificate Validation Matters in 2025
SSL certificates are now mandatory, not optional. Google Chrome marks all non-HTTPS sites as "Not Secure," immediately destroying visitor trust. Beyond basic HTTPS, proper SSL/TLS configuration protects against man-in-the-middle attacks, data interception, and certificate spoofing. A valid, properly configured SSL certificate is the foundation of website security—without it, nothing else matters.
In 2025, SSL certificates do far more than encrypt traffic. They establish website identity, enable trust indicators in browsers, prevent phishing attacks, and directly impact SEO rankings. Google penalizes non-HTTPS sites in search results, and major browsers now warn users before they even reach insecure sites. 84% of users abandon purchases if a site is marked "Not Secure"—SSL errors cost real revenue.
However, having an SSL certificate isn't enough. Common issues include expired certificates (going unnoticed until browsers block your site), incomplete certificate chains (causing trust errors for some visitors), weak cipher suites (vulnerable to attacks), outdated TLS protocols (TLS 1.0/1.1 deprecated), missing HSTS headers (allowing downgrade attacks), and mixed content warnings (HTTPS pages loading HTTP resources).
FounderScan's SSL certificate checker validates all aspects of your HTTPS implementation in under 2 minutes. We don't just check if you have an SSL certificate—we verify expiration dates (with advance warning), validate certificate chains, analyze cipher suite strength, check TLS protocol versions, detect HSTS implementation, identify mixed content issues, and test certificate transparency logging. Each check prevents specific security vulnerabilities and trust problems.
The average website has 3-5 SSL/TLS configuration issues that need attention. These range from critical problems like weak encryption or expired certificates to important optimizations like enabling HSTS or using modern cipher suites. Our free scan shows you exactly what needs fixing, and the affordable detailed report provides step-by-step implementation instructions for each issue.
Comprehensive SSL/TLS Certificate Analysis
Certificate Expiration Monitoring
Prevent catastrophic downtime from expired certificates by monitoring validity periods and renewal status.
- Expiration Date Tracking - Days until certificate expires
- Validity Period Analysis - Issued date and duration check
- Renewal Warnings - Advanced notice before expiration
- Certificate Authority Validation - Trusted CA verification
Certificate Chain Verification
Ensure complete certificate chain from your site to root CA for universal browser trust.
- Intermediate Certificate Detection - Missing chain links
- Root CA Validation - Trusted root certificate check
- Chain Completeness - All certificates present
- Chain Order Validation - Correct certificate sequence
TLS Protocol Version Analysis
Verify modern TLS protocol usage and detect deprecated versions vulnerable to attacks.
- TLS 1.3 Support Detection - Latest protocol availability
- TLS 1.2 Minimum Enforcement - Deprecated protocol detection
- SSL 2.0/3.0 Vulnerability Check - Ancient protocol warnings
- Protocol Downgrade Prevention - Security configuration
Cipher Suite Security Analysis
Validate encryption strength and detect weak or vulnerable cipher suites.
- Strong Cipher Detection - AES-GCM, ChaCha20 support
- Weak Cipher Identification - RC4, DES, 3DES warnings
- Forward Secrecy Validation - Perfect forward secrecy
- Cipher Suite Ordering - Server preference configuration
HSTS Header Implementation
Verify HTTP Strict Transport Security to prevent protocol downgrade attacks.
- HSTS Header Detection - Strict-Transport-Security presence
- Max-Age Configuration - Sufficient duration validation
- Subdomain Coverage - includeSubDomains directive
- Preload List Status - HSTS preload eligibility
Mixed Content Detection
Identify insecure HTTP resources loaded on HTTPS pages that trigger browser warnings.
- HTTP Resource Detection - Images, scripts, stylesheets
- Active Mixed Content - Scripts, iframes vulnerabilities
- Passive Mixed Content - Images, media warnings
- Fix Recommendations - Update resource URLs
How Our SSL Certificate Checker Works
Enter Your Website URL
Simply enter your website URL and our SSL certificate checker immediately begins comprehensive validation. We connect to your server, retrieve the SSL/TLS certificate, and analyze the complete certificate chain from your site to the root certificate authority. The scan completes in under 2 minutes with zero impact on your site performance—completely safe to run on production sites.
Comprehensive SSL/TLS Validation (8+ Checks)
Our specialized SSL scanners validate certificate expiration (with advance warnings), verify complete certificate chains, analyze TLS protocol versions (detecting deprecated protocols), test cipher suite strength, check HSTS implementation, detect mixed content issues, validate certificate transparency logging, and verify trusted certificate authority signatures. Each check prevents specific security vulnerabilities.
Get Your Free SSL Security Score
Instantly see your SSL/TLS security score (A-F grading) with a breakdown of all detected issues by severity. The free scan shows critical problems like expired certificates or weak encryption, medium-priority issues like missing HSTS headers, and optimization opportunities like enabling TLS 1.3. You'll know exactly what needs fixing to achieve A+ SSL security without paying anything.
Unlock Detailed Fix Instructions (Affordable One-Time Fee)
For an affordable one-time payment, get step-by-step instructions for fixing every SSL/TLS issue. Each problem includes server configuration examples (Apache, Nginx, CloudFlare), expected security impact, implementation time estimates, and verification steps. We show you the exact headers to add, which cipher suites to enable, how to configure HSTS, and how to fix mixed content—everything needed to achieve perfect SSL security.
Implement Fixes & Re-Scan to Verify
Follow our detailed instructions to optimize your SSL/TLS configuration. Most fixes take 10-30 minutes to implement through your hosting control panel or server configuration files. Re-scan anytime to verify improvements and watch your SSL security grade improve from C or D to A+. Regular scanning (quarterly) ensures your certificate stays valid and configuration remains secure as standards evolve.
Common SSL/TLS Issues We Find (43% of Sites)
Expired or Expiring Certificates (Found in 12% of Sites)
CRITICALSSL certificates typically expire after 90 days (Let's Encrypt) or 1-2 years (commercial CAs). When certificates expire, browsers block access to your site with scary "Your connection is not private" errors—instant 100% bounce rate. Many site owners don't realize their certificate expired until customers report they can't access the site.
Impact: Complete site inaccessibility. All visitors see error pages. Zero conversions. Catastrophic revenue loss until certificate renewed.
Fix: Enable auto-renewal (Let's Encrypt/Certbot) or set calendar reminders 30 days before expiration. Monitor with SSL certificate checker monthly. Expected time: 15 minutes to configure auto-renewal.
Incomplete Certificate Chain (Found in 18% of Sites)
CRITICALSSL certificates require a complete chain from your site certificate through intermediate certificates to the root CA. Missing intermediate certificates cause "NET::ERR_CERT_AUTHORITY_INVALID" errors for some users (especially mobile). The site works for some visitors but not others, making the problem hard to diagnose and causing inconsistent user experiences.
Impact: 10-30% of visitors see certificate errors and can't access your site. Higher bounce rates, lost conversions, trust damage.
Fix: Install complete certificate chain including all intermediate certificates. Most CAs provide a "fullchain" file—use that. Expected time: 20 minutes to install complete chain.
Weak or Deprecated Cipher Suites (Found in 31% of Sites)
HIGHCipher suites define encryption strength. Weak ciphers like RC4, DES, or 3DES are vulnerable to known attacks. Many servers still support these for "compatibility" with ancient browsers, but this creates real security risks. Attackers can force connections to use weak ciphers and break encryption, exposing customer data, passwords, and payment information.
Impact: Vulnerable to BEAST, CRIME, POODLE attacks. Potential data breaches. Compliance violations (PCI DSS requires strong encryption).
Fix: Disable weak ciphers in server configuration. Enable only AES-GCM, ChaCha20. Configure server cipher preference. Expected time: 30 minutes configuration + testing.
Missing HSTS Header (Found in 67% of Sites)
HIGHHTTP Strict Transport Security (HSTS) forces browsers to always use HTTPS, preventing protocol downgrade attacks. Without HSTS, attackers can intercept the initial HTTP request (before HTTPS redirect) and steal session cookies, credentials, or inject malicious code. HSTS also prevents users from clicking through certificate warnings, protecting against man-in-the-middle attacks.
Impact: Vulnerable to SSL stripping attacks. First-visit interception. Users can bypass certificate warnings. Reduced security scores.
Fix: Add Strict-Transport-Security header with max-age=31536000; includeSubDomains; preload. One-line server configuration. Expected time: 10 minutes.
Outdated TLS Protocol Versions (Found in 24% of Sites)
MEDIUMTLS 1.0 and 1.1 are officially deprecated by major browsers and vulnerable to attacks. Sites still supporting these protocols are at risk. While TLS 1.2 is acceptable, TLS 1.3 offers significant security and performance improvements— 30% faster connections with stronger encryption. Modern browsers support TLS 1.3, making older versions unnecessary.
Impact: Vulnerable to known TLS 1.0/1.1 attacks. Slower connection establishment. Compliance violations. Browser warnings possible.
Fix: Disable TLS 1.0/1.1 in server configuration. Enable TLS 1.2 minimum, TLS 1.3 preferred. Expected time: 20 minutes configuration.
Why Choose FounderScan's SSL Certificate Checker?
Multi-Dimensional Analysis
Unlike tools checking only SSL, FounderScan analyzes SSL/TLS alongside security vulnerabilities (35%), SEO (25%), performance (25%), and compliance (15%)—complete website health in one scan.
Affordable & No Subscriptions
Free SSL scan shows all issues. Affordable one-time fee unlocks detailed fixes—no monthly subscriptions, no hidden costs. Pay once per scan, not every month like monitoring services.
Actionable Configuration Examples
We provide exact server configurations (Apache, Nginx, CloudFlare) for every issue. Not just "enable HSTS"—we show you the exact lines to add to your config files with verification steps.
Frequently Asked Questions
What is an SSL certificate checker?
An SSL certificate checker validates your website's SSL/TLS configuration including certificate expiration, chain completeness, cipher suite strength, TLS protocol versions, HSTS implementation, and mixed content detection. The best SSL checkers provide actionable fix instructions with server configuration examples, not just a grade or score.
How long does an SSL certificate check take?
FounderScan's SSL certificate checker completes in under 2 minutes. We connect to your server, retrieve the SSL certificate and chain, analyze TLS protocols and cipher suites, check HSTS implementation, and scan for mixed content—all validated simultaneously for fast, comprehensive results.
What does a free SSL certificate check include?
FounderScan's free SSL check shows your SSL security grade (A-F), total issue count, and severity breakdown. You see exactly how many critical, medium, and low-severity problems exist in certificate validity, chain configuration, cipher suites, TLS protocols, HSTS, and mixed content. Unlock detailed fix instructions with an affordable one-time fee.
Why is my SSL certificate showing as invalid?
Common reasons include: (1) Expired certificate—needs renewal, (2) Incomplete certificate chain—missing intermediate certificates, (3) Name mismatch—certificate domain doesn't match your site, (4) Self-signed certificate—not trusted by browsers, or (5) Revoked certificate—compromised and invalidated by CA. Run our SSL checker to identify the specific issue and get fix instructions.
What is HSTS and why does it matter?
HTTP Strict Transport Security (HSTS) is a security header that forces browsers to always use HTTPS, preventing protocol downgrade attacks. Without HSTS, attackers can intercept the initial HTTP request and steal data before the HTTPS redirect happens. HSTS also prevents users from clicking through certificate warnings, protecting against man-in-the-middle attacks. Implementation takes 10 minutes but dramatically improves security.
How often should I check my SSL certificate?
Check your SSL certificate quarterly at minimum, or monthly if using short-lived certificates (Let's Encrypt 90-day). Also check after: certificate renewals, server configuration changes, adding new subdomains, or if users report certificate errors. Regular monitoring prevents expiration-related downtime and catches configuration issues before they impact users.
What is a good SSL security grade?
A good SSL security grade is A or A+. Grade A indicates strong encryption, modern TLS protocols, and proper configuration. A+ additionally includes HSTS with preloading. Grades B or C need improvement (weak ciphers or old protocols). Grades D, E, or F indicate critical security problems requiring immediate fixes. Most sites can achieve A+ with 30-60 minutes of server configuration using our detailed fix instructions.
Do I need to pay for an SSL certificate?
Free SSL certificates from Let's Encrypt are excellent and trusted by all browsers. They're perfect for most websites and auto-renew every 90 days. Paid certificates ($50-$300/year) offer longer validity (1-2 years), wildcard support for unlimited subdomains, Extended Validation (EV) for company name in browser, and customer support. For startups and small businesses, Let's Encrypt is recommended—save money and use FounderScan to validate configuration.
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