Do I enter a URL or a domain name?

Either is fine. If a URL is entered, our tool automatically extracts the domain part and checks it.

What happens if a certificate expires?

Browsers will display a large warning screen like "Your connection is not private," and users will be unable to view the site. It also negatively impacts SEO, so be sure to renew it before it expires.

Is the data saved on the server?

No. Our tool communicates from its server to the target domain to retrieve the certificate, but search history and entered data are never saved on our server.

What is the difference between free SSL (like Let's Encrypt) and paid SSL?

There is no difference in encryption strength. The main differences are the "level of validation (domain validation vs. organization validation)" and "support/warranty." For personal blogs and small sites, free SSL is usually sufficient.

What is an intermediate certificate error?

It is an error that occurs when the intermediate certificate is not correctly installed on the server side. It causes warning screens on some browsers (especially mobile), requiring server reconfiguration.

When should I renew my certificate?

It is common to renew it about "30 days before" the expiry date. Recently, using automated renewal tools (like Certbot) to renew automatically a few weeks before expiry has become the mainstream.

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ssl checker,

SSL Certificate Checker

Instantly retrieve and display SSL/TLS certificate information for any website.
Quickly check the remaining days until expiration and the issuer.

⚡

Instant Check

Just enter the domain

📅

Visualize Expiry

Prevent missing renewals

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No Signup

Completely free to use

about,

About the SSL Certificate Checker

SSL/TLS certificates are essential elements for encrypting website communications and protecting user safety. However, certificates have an expiration date, and forgetting to renew them will make the site inaccessible, causing significant damage to the business.

This tool directly retrieves the SSL certificate of the specified domain from the server and instantly visualizes information such as the remaining days of validity and the issuing organization (Certificate Authority). This helps prevent missed certificate renewals and security issues before they occur.

how to,

How to check certificate info

STEP 1

Enter Domain Name

Enter the domain name (e.g., digrart.jp) or URL you want to check in the input field.

STEP 2

Run Check

Click the "Check" button, and our tool's server will start communicating with the target HTTPS port (443) in the background.

STEP 3

View Results

Detailed information retrieved from the server, such as the certificate's validity period, remaining days, and issuer, will be displayed. If the remaining days are low, please proceed with the renewal process early.

glossary,

SSL/TLS Glossary

SSL/TLS Certificate: A digital certificate that encrypts communication between the server and the browser, proving that the site operator is genuine. Essential for secure communication.
Issuer / CA: Stands for Certificate Authority. Refers to a trusted third-party organization, such as Let's Encrypt or GlobalSign, that reviews and issues certificates.
Validity Period: The period during which the certificate is valid. Recently, for improved security, the validity period of SSL certificates has been limited to 398 days (about 13 months) or less, requiring regular renewal.
SANs (Subject Alternative Names): A list of additional domain names specified to protect multiple domain names (such as subdomains) with a single certificate.
Let's Encrypt: A free, automated, and open certificate authority (CA) run for the public's benefit. Used by numerous websites worldwide. The validity period is short, at 90 days.
Intermediate Certificate: A certificate that bridges the root certificate authority and the server certificate. If not configured correctly on the web server, the visitor's browser may not be able to verify the authenticity of the server certificate and may display a warning.
TLS 1.3: Currently the latest version of the encryption protocol. Compared to the previous version (TLS 1.2), it offers improved connection speeds and enhanced security.
Public Key / Private Key: A pair of keys used in the "public key cryptography" method that supports SSL/TLS communication. The browser encrypts data with the public key, and the server decrypts it with its private key, which only it possesses.

faq,

Frequently Asked Questions (FAQ)

Q.Do I enter a URL or a domain name?: Either is fine. If a URL is entered, our tool automatically extracts the domain part and checks it.
Q.What happens if a certificate expires?: Browsers will display a large warning screen like "Your connection is not private," and users will be unable to view the site. It also negatively impacts SEO, so be sure to renew it before it expires.
Q.Is the data saved on the server?: No. Our tool communicates from its server to the target domain to retrieve the certificate, but search history and entered data are never saved on our server.
Q.What is the difference between free SSL (like Let's Encrypt) and paid SSL?: There is no difference in encryption strength. The main differences are the "level of validation (domain validation vs. organization validation)" and "support/warranty." For personal blogs and small sites, free SSL is usually sufficient.
Q.What is an intermediate certificate error?: It is an error that occurs when the intermediate certificate is not correctly installed on the server side. It causes warning screens on some browsers (especially mobile), requiring server reconfiguration.
Q.When should I renew my certificate?: It is common to renew it about "30 days before" the expiry date. Recently, using automated renewal tools (like Certbot) to renew automatically a few weeks before expiry has become the mainstream.