SSL Certificate Finder
An SSL certificate finder lets you check a domain's live SSL certificate details and verify whether the certificate chain is valid.
Why we use SSL today
Even though people still say SSL, the security used by HTTPS today is TLS. TLS is used to:
- Encrypt data in transit.
- Prevent tampering.
- Verify the site's identity using trusted Certificate Authorities.
What Are Ciphers?
In SSL/TLS, a cipher suite is the set of cryptographic methods used to protect the connection. It matters because even with a valid certificate, weak encryption choices can reduce security.
For SSL/TLS, cipher suites are relevant because they determine:
- Encryption strength: how the data is encrypted after the handshake.
- Integrity: how the connection detects if data was altered in transit.
- Key agreement: how the client and server create shared keys safely.
How to Use Our SSL Certificate Checker Tool
The following steps outline how to check SSL certificates using our tool:
- Simply enter the domain in the input box whose SSL certificate and chain you want to lookup.
- Click on the SSL Lookup button.
- In seconds, you will get results for the SSL certificate(s) for the given domain with the following necessary fields:
- SSL Server Certificate: The main certificate currently served by the domain.
- Issued For: The certificate's "Subject" (the domain name the certificate is intended to secure). For modern certificates, this usually works together with SANs.
- Issued By: The Certificate Authority (CA) that issued the certificate. This helps identify who vouches for the certificate.
- SSL Chain Validation: Whether the full certificate chain validates successfully. If this fails, many clients/browsers will show trust errors.
- Subject Alternative Names (SANs): The full list of domains covered by the certificate. SANs are what browsers primarily check to match the hostname.
An SSL checker tool helps verify if the SSL certificate is correctly installed and provides details about the SSL installation status.
Using an SSL certificate checker is a better method than just looking for https in the URL, as it provides up-to-date and detailed information about whether the certificate is installed and valid.
How SSL Certificate Checking Works with OpenSSL
When you run an SSL certificate check, the checker behaves like a browser and uses the TLS protocol to test what the server presents in real time.
- The checker initiates a TLS connection to the domain. Tools and servers commonly rely on OpenSSL to perform this negotiation.
- A TLS handshake is performed and the server sends its certificate(s). During the handshake, the server presents:
- the server (leaf) certificate, and
- usually intermediate certificate(s) which might be needed to link to a trusted root.
- During this TLS handshake, the client and server securely agree on temporary session keys that are used to encrypt/decrypt the connection. An SSL certificate check focuses on verifying trust and configuration.
- The checker validates the certificate chain using trust stores. Using OpenSSL-style certificate verification rules, the checker confirms:
- the leaf certificate is issued (signed) by an intermediate CA,
- the chain is complete and correctly ordered.
- It verifies the certificate matches the domain name (SAN). Modern validation checks the hostname against Subject Alternative Names (SANs), which is what browsers primarily use to confirm the certificate is for the requested domain.
- It checks certificate validity and security properties. The checker reads:
- Valid From / Valid To (expiry),
- whether the certificate is currently trusted,
- whether the connection negotiates a modern TLS version and secure settings.
SSL/TLS Versions
Currently used:
- TLS 1.3 (current state-of-the-art standard)
- TLS 1.2 (still widely used and supported; many environments require at least this level)
Deprecated:
- TLS 1.0 and TLS 1.1 are formally deprecated and moved to Historic status due to weak/obsolete cryptographic support.
- Legacy SSL versions are considered obsolete in modern security contexts (and are not treated as strong cryptography in common compliance guidance).
Types of SSL/TLS Certificates
You can classify certificates in the following ways:
1) By validation level (Identity)
- DV (Domain Validated): Proves domain control
- OV (Organization Validated): Proves domain control and organization identity
- EV (Extended Validated): Stricter organization identity verification
2) By coverage (Which domains are included)
- Single-Domain Certificate: Covers one exact hostname (e.g., example.com).
- Wildcard Certificate: Covers subdomains under one domain (e.g., *.example.com covers api.example.com). Usually does not cover the root domain unless it's also included separately.
- Multi-Domain / SAN (UCC) Certificate: Covers multiple different hostnames inside one certificate using SANs (e.g., example.com, www.example.com, api.example.com, example.net).
3) By purpose (What it's meant to secure)
- TLS Server Certificate: Used for HTTPS websites, APIs, CDNs, load balancers.
- Client Certificate: Used when a server must verify the client (not just the server). Common in enterprise APIs, internal services, banking integrations.
- S/MIME Certificate: Used to sign emails (prove sender identity) and/or encrypt email content.
- Code Signing Certificate: Used to sign software so users/OS can verify it hasn't been modified and is from a known publisher.
What is an SSL Certificate Chain?
An SSL certificate chain is the set of certificates a server presents so a browser/client can verify the site is trusted.
It usually has 3 parts:
- Server (leaf) certificate: Issued for your domain. This is the certificate your site actually uses.
- Intermediate certificate(s): Intermediate certificates are optional and may or may not be present. There can be one or more intermediate certificates or they might not exist in the chain. They are issued by a trusted authority and used to bridge trust from the server certificate up to a root. Most public CAs use intermediates.
- Root certificate: The trusted top-level CA certificate that is already stored in browsers/OS trust stores. The server typically does not need to send the root because clients already have it.
Our tool also shows certificate chain information for the domain.
- The chain should include the server (leaf) certificate, any intermediate certificate(s), and link up to a trusted root in client trust stores.
- If the chain is incomplete or misconfigured, you'll see chain validation failures, even if the leaf certificate looks fine.
What are SANs and why they matter in SSL?
SANs (Subject Alternative Names) are the official list of domain names a certificate is allowed to secure.
- Modern certificates put the real domain coverage inside SANs.
- During SSL/TLS verification, browsers/tools check: "Is the exact hostname I'm visiting listed in the certificate's SANs?"
- Example coverage patterns:
- example.com and www.example.com must be explicitly listed (unless both are included).
- A wildcard like *.example.com covers api.example.com but does not cover example.com itself.
- Multi-domain certificates can have many SAN entries (useful for SaaS, CDNs, multi-tenant systems).
So, SANs answer one key question: "Is this certificate valid for this domain?"
SSL validation methods
When someone says SSL validation there are two different types people mean:
1) Domain validation methods
These are the common ways certificate authorities validate ownership for DV certificates:
- DNS validation: You add a specific DNS record. If it matches, you've proven control of the domain.
- HTTP validation: You place a specific file/token at a required URL on the domain (served over HTTP/HTTPS).
- Email validation: Approval link/code goes to an authorized domain email (like admin@ / webmaster@).
This is about getting the certificate issued.
2) Connection validation methods
This is what your SSL checker does when it tests a live domain:
- Chain of trust validation: Confirms the server certificate links through intermediates to a trusted root CA.
- Hostname verification: Confirms the domain you entered matches a SAN entry.
- Validity period check: Confirms current date is within Valid From / Valid To.
- TLS version & security settings check: Reports whether modern TLS is used and flags weak configurations.
- Revocation checking: Some clients attempt to confirm the cert wasn't revoked (commonly via OCSP/CRL mechanisms), though behavior varies by client/app.
How to Renew an SSL Certificate
- Check the expiry date and plan the renewal early. Renewing early prevents browser warnings and unexpected outages.
- Generate a new certificate from your provider/CA. In most setups, renewal means the CA issues a new certificate. Publicly trusted TLS issuance follows CA/Browser Forum rules.
- Complete validation if required. Some renewals reuse recent validation, but many cases require confirming domain control again under CA rules/policy.
- Deploy the new certificate to wherever TLS terminates. Install it on your server / CDN / load balancer. Make sure the server presents the server certificate + intermediate certificates (if needed).
- Reload/restart the service so the new certificate goes live. Without a reload, many servers keep using the old certificate.
- Re-check with your SSL Certificate Finder to confirm the renewal is live. Confirm:
- the new Valid To (expiry) date is now being served, and
- chain validation is successful (trusted CA path).
FAQs
SSL (Secure Sockets Layer) is the older name for the technology that secures connections between clients and servers. In practice today, when people say SSL, they usually mean TLS encryption used for HTTPS.
An SSL certificate is a digital certificate that:
- binds a domain name to a cryptographic key, and
- is signed by a trusted Certificate Authority (CA),
so clients can establish an encrypted HTTPS connection and validate the domain.
TLS is the modern protocol used today. SSL is the legacy predecessor. Most systems and tools still say SSL out of habit, but real-world HTTPS security is TLS.
The standard process is:
- Choose a CA (or use your hosting/provider's built-in option).
- Create and generate a private key + CSR (certificate signing request).
- Complete domain validation (usually DNS or HTTP validation).
- Install the issued certificate + any intermediate certificates on your server/CDN/load balancer.
- Verify with an SSL certificate checker tool.
- Check the certificate's Valid To (expiry) date using an SSL Certificate Finder. If today is after the Valid To date, the certificate is expired.
- You may also see browser warnings like "Your connection is not private" or "Certificate expired" when visiting the site.
- If you renewed your certificate after expiry, re-check to confirm the new expiry date is live and certificate chain validation is successful.