Frequently Asked Questions (FAQ)
What is an SSL certificate?
An SSL (Secure Sockets Layer) certificate is a digital certificate that authenticates a website’s identity and enables an encrypted connection. It helps protect data such as passwords, credit card numbers, and personal information from interception by unauthorized parties.
How to do Curl Requests?
To check a domain's SSL certificate, use these endpoints:
- Human - Easy to read: /curl/domain.com
- JSON: /crj/domain.com
- XML: /crx/domain.com
Auto mode chooses IPv4 or IPv6. Force a specific IP version with:
- IPv4: /crj/ipv4/domain.com or /crx/ipv4/domain.com
- IPv6: /crj/ipv6/domain.com or /crx/ipv6/domain.com
Output includes certificate details, validity, issuer info, chain validation, and the IP used.
Example: curl "https://checkssl.eu/crj/example.com"
How do I use this SSL Checker?
Enter the domain you want to check in the input box and select whether you want to check IPv4, IPv6, or both. Then click “Check” to retrieve detailed information about the SSL certificate and its validation status.
Why do some certificates show as invalid?
Certificates can be invalid for several reasons including expiration, hostname mismatch, or an untrusted certificate authority. This tool highlights these issues to help you identify problems.
What does “Chain Valid” mean?
The certificate chain links your website's certificate to a trusted root authority. If any certificate in the chain is missing or untrusted, browsers may warn visitors about security risks.
Why are there options for IPv4 and IPv6?
Some domains are accessible via both IPv4 and IPv6. Because configurations and certificates might differ between the two, the tool lets you test both to ensure full coverage.
Is my data safe when using this tool?
Yes. The SSL Checker only performs standard SSL/TLS connections to the domain you enter. It does not store, log, or share your queries.
Can this tool check internal or private network certificates?
No. This tool only works with publicly accessible domains on the internet.
How often should I check my SSL certificates?
Regularly monitoring your certificates is important. We recommend checking at least once a month or before any major website changes.
What is the SSL Certificate Chain?
The SSL certificate chain is a sequence of certificates, starting from your website’s certificate (leaf), through one or more intermediate certificates, up to a trusted root certificate authority (CA). This chain establishes trust because browsers recognize the root CA as a trusted entity.
If any certificate in this chain is missing, expired, or untrusted, browsers will display security warnings.
What is TLS and why is it important?
TLS (Transport Layer Security) is the modern cryptographic protocol that secures internet connections by encrypting data exchanged between your browser and a server. TLS versions 1.2 and 1.3 are considered secure, while older versions (like TLS 1.0 and 1.1) have known vulnerabilities.
This tool reports the TLS version your server supports to help you ensure your website uses up-to-date security standards.
What are the differences between Let’s Encrypt and paid SSL certificates?
Let’s Encrypt is a free, automated certificate authority that issues Domain Validation (DV) certificates. These are suitable for most websites, providing strong encryption and quick issuance.
Paid SSL certificates may include additional validation types:
- Organization Validation (OV): Confirms the organization’s identity, increasing trust.
- Extended Validation (EV): Offers the highest level of validation, showing the organization’s name in the browser address bar.
Paid certificates often come with additional benefits like warranty coverage, customer support, and insurance.
What is warranty or insurance in SSL certificates?
Many paid SSL certificates include a warranty or insurance that compensates users if a certificate authority mistakenly issues a certificate to a fraudulent party that causes financial loss.
This warranty does not protect your website or business directly but provides financial protection to end users in rare cases of certificate misuse or failure.
Let’s Encrypt certificates do not include warranties because they are free and automated.