Free SSL Certificate Checker & TLS Scanner
Verify SSL/TLS certificate validity, inspect Certificate Authority issuer, calculate expiration dates, and test TLS 1.3 encryption strength.
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How to Use Free SSL Certificate Checker & TLS Scanner
Enter any domain name or website URL (e.g. stripe.com or yoursite.com) into the SSL checker.
Click 'RUN AUDIT' to execute real-time TLS certificate analysis.
Inspect the Certificate Authority issuer, valid from date, and expiration date.
Check days remaining until expiration and verify TLS 1.3 cipher suite security.
Free SSL Certificate Checker & TLS Scanner — Technical Verification Mechanics
Free SSL Certificate Checker & TLS Scanner performs real-time queries against public DNS over HTTPS (DoH) endpoints, RDAP/WHOIS databases, SSL Certificate Transparency logs, and RFC protocol standards.
Zero-Retention Privacy Guarantee
Queries are executed statelessly directly in your browser or edge isolate. No scan queries, target URLs, or IP logs are saved to databases.
Real-Time RFC Compliance
Validates RFC 7208 (SPF), RFC 6376 (DKIM), RFC 7489 (DMARC), and TLS 1.3 standards to deliver accurate diagnostic feedback.
Free SSL Certificate Checker & TLS Scanner — Frequently Asked Questions
Why does my browser say a site is "Not Secure" even with a padlock?
This can happen with mixed content (loading some resources over HTTP) or an outdated certificate — an SSL checker diagnoses the specific cause.
Can I check the SSL certificate of a subdomain separately?
Yes, enter the exact subdomain (e.g., shop.example.com) — certificates can differ between a root domain and its subdomains, especially with wildcard vs. single-domain certs.
What does "SSL chain of trust" mean and why does it matter?
It refers to the certificate being properly linked to a trusted root Certificate Authority; a broken chain can trigger browser warnings even if the certificate itself is technically valid.
How far in advance should I renew my SSL certificate?
Best practice is renewing at least 2–4 weeks before expiration to avoid downtime, especially since many CAs now issue shorter 90-day certificates.
Does an SSL checker verify the certificate issuer (CA)?
Yes, it shows which Certificate Authority issued the cert (Let's Encrypt, DigiCert, Sectigo, etc.), useful for verifying authenticity and catching self-signed certs.
Can free SSL certificates (like Let's Encrypt) be checked the same way?
Yes, an SSL checker treats free and paid certificates identically, verifying validity, expiration, and chain regardless of the issuing authority.
How do I check if a website's SSL certificate is valid?
Enter the domain into an SSL checker — it instantly verifies the certificate's validity, issuer, expiration date, and whether the chain of trust is complete.
What happens if an SSL certificate expires?
Browsers show visitors a security warning and block or discourage access, which can hurt trust and traffic; an SSL checker helps you catch expiration before it happens.
Does having an SSL certificate mean a site is trustworthy?
Not entirely — SSL encrypts the connection, but even phishing sites can have valid SSL certificates, so it should be one signal among several, not the only one.
How often should I check my SSL certificate status?
Most certificates last 90 days to 1 year, so checking monthly (or setting up expiration alerts) prevents unexpected downtime or browser warnings.
What's the difference between SSL and TLS?
TLS is the modern, more secure successor to SSL, but 'SSL' is still the common industry term used for both — an SSL checker typically verifies TLS certificates today.
How does this compare to Qualys SSL Labs?
Qualys SSL Labs offers a deep technical grade (A+ to F) covering cipher strength and protocol support, while a quick SSL checker is faster and better suited for a simple validity/expiration check.
Can I check the SSL certificate of an internal or private server?
Only if the checker can reach that server's public-facing address; purely internal/private network servers generally require a local tool rather than a web-based checker.
How do I detect if a certificate is self-signed rather than CA-issued?
An SSL checker flags self-signed certificates specifically, since browsers don't trust them by default and they trigger security warnings for visitors.
What TLS version should my website be using in 2026?
TLS 1.2 is the minimum acceptable standard, with TLS 1.3 recommended for best security and performance; an SSL checker typically reports which version(s) your server supports.
Is there a command-line way to check SSL certificates without a web tool?
Yes, 'openssl s_client -connect domain:443' shows certificate details in the terminal, though a web-based SSL checker presents the same data more readably for non-developers.
Does an SSL checker show if my certificate covers all necessary subdomains?
Yes, it displays the Subject Alternative Names (SANs) on the certificate, letting you confirm whether it's a wildcard cert or only covers specific subdomains.
What is an SSL checker and why does every website need one?
It's a tool that verifies whether a website's encryption certificate is valid, current, and properly configured — essential for protecting visitor data and maintaining browser trust.
Why is SSL especially critical for e-commerce and WooCommerce stores?
Payment and personal data transmitted during checkout must be encrypted; an invalid or expired SSL certificate can expose customer data and trigger browser warnings that kill conversions instantly.
Do healthcare websites have specific SSL requirements?
Yes, healthcare sites handling patient data typically need to meet HIPAA-related security expectations, and a valid, properly configured SSL certificate is a baseline requirement for compliant data transmission.
Is SSL checking part of PCI DSS compliance for businesses accepting payments?
Yes, PCI DSS requires strong encryption for cardholder data in transit, and regularly verifying SSL certificate validity is a standard part of maintaining compliance.
Why would a law firm's website need a strong SSL setup?
Law firms often handle sensitive client communications and documents through their websites, making certificate validity and proper HTTPS enforcement important for confidentiality and client trust.
Do SaaS companies need to check SSL across multiple subdomains (app, api, dashboard)?
Yes, SaaS platforms typically run several subdomains for different services, each needing its own valid certificate — an SSL checker should be run against each one individually.
What is an SSL certificate checker and why is it important?
An SSL certificate checker verifies that a website's HTTPS encryption certificate is valid, not expired, issued by a trusted Certificate Authority (CA), and properly installed. It checks certificate chains, TLS protocol versions (TLS 1.2 / TLS 1.3), cipher suites, and Subject Alternative Names (SANs).
How to check if an SSL certificate is valid online?
Enter any domain into IncogSay's free SSL checker and click 'RUN AUDIT'. The tool checks Certificate Transparency logs and live TLS handshake parameters to confirm issuer authority, validity dates, days remaining until expiration, and cipher strength.
What happens when an SSL certificate expires?
When an SSL certificate expires, web browsers (Chrome, Safari, Edge, Firefox) display severe security warnings ('Your connection is not private' or 'NET::ERR_CERT_DATE_INVALID'), blocking visitors and causing immediate traffic and revenue loss.
How many days in advance should I renew my SSL certificate?
Security best practices recommend renewing SSL/TLS certificates at least 15–30 days before expiration. Most modern CAs (like Let's Encrypt, Cloudflare, DigiCert) issue 90-day certificates with automated renewal hooks.
What is a Subject Alternative Name (SAN) in an SSL certificate?
A SAN allows a single SSL certificate to secure multiple domain names and subdomains (e.g. 'example.com', 'www.example.com', 'api.example.com'). Our SSL scanner lists all SANs attached to the certificate.
How to verify if my site is using TLS 1.3 encryption?
TLS 1.3 provides enhanced security and faster connection handshakes compared to legacy TLS 1.0/1.1 (which are deprecated). IncogSay's SSL cert checker confirms the negotiated TLS protocol version.
Can an SSL certificate check detect man-in-the-middle attacks?
Yes. An SSL check confirms that the certificate is signed by a root CA in browser trust stores, ensuring traffic between the client and server cannot be intercepted or tampered with.
Is IncogSay's SSL certificate checker free?
Yes. IncogSay provides a 100% free online SSL checker, SSL cert validator, certificate scanner, and expiration date tool.