Paste any URL and get a full SSL/TLS report in seconds — certificate issuer, expiry date, chain integrity, supported TLS versions, HSTS status and HTTPS redirect configuration. No signup, no email, no limits.
Running SSL/TLS analysis…
Most website owners set up an SSL certificate once, see the padlock appear in the browser, and never think about it again. That's the problem. Certificates expire. Chains break after server migrations. Cipher suites get deprecated by browser vendors without any warning to you. And every one of those silent failures shows up to your visitors as a full-page red warning that says "Your connection is not private."
We built this SSL Checker because we kept running into the same thing: sites that "have HTTPS" but whose certificates had quietly expired, or whose TLS configuration still allowed protocols that browsers stopped trusting years ago. A green padlock in your own browser doesn't tell you any of that — because your browser is probably caching an old session, or you're testing on a network that trusts a stale cert.
This tool connects to your server from the outside, exactly like a first-time visitor would, and reports what they'd actually see.
Every check runs against your live server — not a cached copy, not a database of known certificates, not a third-party API. We open a real TLS connection to your hostname on port 443, retrieve the certificate the server presents, and walk the full chain back to the root authority.
notBefore and notAfter dates from the certificate
itself, plus how many days you have left before renewal.
Strict-Transport-Security header is present and read the
max-age value. HSTS is what prevents downgrade attacks on the
very first visit.
After running thousands of checks, the same handful of problems come up over and over. None of them are exotic — they're all preventable, and most take less than five minutes to fix once you know they exist.
This is the classic. A team migrates to a new host, sets up the site, tests it — everything works. Then three months later the old certificate auto-renewal doesn't fire because it was tied to the old server. The site goes dark for visitors until someone notices.
We've seen a production e-commerce site take orders for 11 hours over an expired certificate. Browsers showed the interstitial warning, customers clicked through, but their confidence was gone. Refund requests spiked 40% that week.
This tool shows days remaining in red the moment a certificate drops below 30 days, and orange below 7 — so you have time to renew without a scramble.
www subdomains
Your certificate covers example.com but not
www.example.com. Anyone who types the www prefix
gets a hard browser warning. This happens constantly on sites where the
certificate was issued for the bare domain but the DNS still resolves both.
Browsers stopped supporting TLS 1.0 and 1.1 back in 2020. If your server still advertises them, you're not just running insecure protocols — you're also failing PCI-DSS compliance and modern browser security audits. The fix is usually one line in your web server config, but you have to know it's happening first.
Without HSTS, a user's very first HTTP request to your site can be intercepted by an attacker on the same network (coffee shop wifi, hotel, airport) and redirected to a fake HTTPS page with a matching but fraudulent certificate. Most website owners have never heard of HSTS. It takes 30 seconds to enable once you know about it.
This is important, and most SSL checkers won't say it: an SSL certificate proves two things — that the connection is encrypted, and that the server you connected to holds the private key for the domain you requested. That's it.
It says nothing about whether the website behind it has:
HttpOnly and Secure flagsSSL is the lock on the front door. It doesn't tell you whether the front door is attached to a house or a cardboard box. For that, you need a full security audit — which is exactly what our website security scanner does. If this SSL check flags any warnings, run the full scan next to see the complete picture.
For most sites: once a month is enough, plus always after:
If you're on Let's Encrypt — which auto-renews every 90 days — the tool is still worth running after any config change. Auto-renewal fails silently more often than you'd expect, and Let's Encrypt sends you warning emails only if you configure contact addresses correctly.
Certificate problems almost always get fixed by re-issuing with your host or certificate authority. Let's Encrypt renewals are usually one command. Paid certificates are re-issued through the CA's dashboard.
Server configuration issues — TLS versions, HSTS headers, HTTPS redirects —
are handled at the web server level. For Nginx, that's usually a few directives
in the server block. For Apache, it's ssl.conf. And
every managed hosting panel from cPanel to Plesk has a section for these
settings.
If you're not sure where to start, paste your domain into the checker above and share the results with your hosting provider. The report gives them exactly the information they need to fix whatever's wrong.
An SSL certificate checker is a tool that connects to a website the same way a first-time visitor's browser would — over a real TLS connection on port 443 — and inspects the certificate the server presents. It reads the certificate's validity dates, issuer, hostname coverage, and cryptographic details, then walks the full chain back to the root CA.
Unlike a browser, which only tells you "the padlock is there" or "the padlock is broken," a dedicated checker surfaces the underlying details: exact expiry date, missing intermediates, deprecated TLS versions, and whether HSTS is enforced. It's the difference between a green/red indicator and an actual report.
Enter your domain in the field above and click "Check SSL." The tool will connect to your server and report whether the certificate is currently in its valid period, who issued it, when it expires, and whether it covers the exact hostname you entered.
If you get a "Secure" result with a green badge, your certificate is doing its job. If you get a "Warnings" or "Attention Required" result, the Issues & Recommendations section will list the exact problems found and what to do about them.
After running a check, look at the Certificate Details section. You'll see the exact start date, the exact expiry date, and the number of days remaining. Our tool color-codes the days-remaining value: green if you have more than 30 days, amber between 7 and 30 days, and red below 7.
If you want a monthly reminder, most certificate authorities (Let's Encrypt via Certbot, Namecheap, DigiCert, etc.) will email you 30, 14, and 7 days before expiry — but only if your contact email on file is current. We recommend verifying that once a year.
TLS 1.0 was standardized in 1999 and TLS 1.1 in 2006. Both rely on cryptographic primitives — MD5/SHA-1 signatures, CBC-mode cipher construction, and weak handshake protections — that have since been broken or significantly weakened by academic research.
Google, Mozilla, Apple, and Microsoft all removed support for both protocols from their browsers between 2018 and 2020. If your server still accepts them, you're not gaining any real compatibility — you're just expanding your attack surface. PCI-DSS and most compliance frameworks now explicitly prohibit them. Disable both; keep only TLS 1.2 and TLS 1.3.
HSTS stands for HTTP Strict Transport Security. It's a response header
(Strict-Transport-Security) that tells the browser: "for
the next N seconds, only ever connect to this domain over HTTPS — never
over HTTP, even if the user types http://."
Without HSTS, an attacker on the same network can intercept a user's very first request to your site — before any redirect to HTTPS happens — and serve a fake page or steal session cookies. This is called a downgrade attack, and it's the reason HSTS was invented.
Enabling HSTS is typically a single line in your web server config.
Start with a short max-age (like 300 seconds) while you
verify nothing breaks, then ramp it up to a year and add
includeSubDomains once you're confident.
In practice, nothing — the terms are used interchangeably. SSL (Secure Sockets Layer) was the original protocol, developed by Netscape in the mid-1990s. TLS (Transport Layer Security) is its successor, standardized by the IETF in 1999 as SSL 3.1, and renamed to avoid confusion.
All modern "SSL certificates" are technically TLS certificates. The industry kept calling them SSL because the name stuck. When you see "SSL Checker" or "SSL/TLS Checker" on a tool page, they mean the same thing.
Typically 3 to 10 seconds. The tool opens multiple TLS connections to test individual protocol versions (1.0, 1.1, 1.2, 1.3), plus one HTTP request to check the redirect, plus one HTTPS HEAD request for HSTS.
If the site is slow to respond, the check can take longer — up to about 30 seconds in the worst case. Servers behind aggressive rate limiting or WAFs may respond slower than normal.
Yes. SSL checks are read-only and public — they connect to the server the same way any browser does. There's no authentication or bypass involved, so checking any publicly accessible HTTPS site is completely fine.
The one thing we can't do is check private or internal addresses
(192.168.x.x, 10.x.x.x, localhost,
or sites behind a VPN). Those are blocked for security reasons.
No. This is the single biggest misunderstanding about SSL. A valid certificate proves the connection is encrypted and the server holds the correct private key for the domain. It says nothing about whether the website itself is well-built.
A site can have a perfectly valid, freshly-renewed certificate and still be vulnerable to SQL injection, cross-site scripting, broken authentication, or any of the OWASP Top 10. SSL is one layer — an important one, but just one.
For a complete picture, run our full website security scanner, which tests headers, cookies, input surfaces, and dozens of other checks.
Technically, very little for the encryption itself. Both Let's Encrypt (free) and DigiCert (paid) issue certificates with the same TLS strength — the browser can't tell the difference, and neither can your visitors.
The differences are in:
For 95% of websites, Let's Encrypt is completely sufficient. Paid certificates are mainly for enterprise compliance requirements.
Yes — completely free, no account required, no rate limit for reasonable use. The tool runs on the same infrastructure as our full security scanner and is supported by non-intrusive advertising.
If you find it useful, the biggest help is telling other website owners and developers about it — or creating a free account to run the deeper full security scan.
Get quick access to your security scans directly from your device.
Tap the Share icon below, then select "Add to Home Screen".