---
title: SSL Certificate Checker — Expiry, Issuer & SANs Online
url: https://varstatt.com/toolkit/ssl
description: Check SSL/TLS certificate details for any domain. Expiry dates, issuer, Subject Alternative Names, protocol, and cipher suite.
section: Developer Toolkit (https://varstatt.com/toolkit)
tags: network
related: DNS (https://varstatt.com/toolkit/dns), SSL (https://varstatt.com/toolkit/ssl), CORS (https://varstatt.com/toolkit/cors)
---
# SSL Certificate Checker

Check SSL/TLS certificate details for any domain. Expiry dates, issuer, Subject Alternative Names, protocol, and cipher suite.

## How It Works

1. **Enter a domain** — Type a domain name like example.com. No protocol or path needed — the tool connects directly to port 443.
2. **See certificate details** — View the subject, issuer, validity dates, days remaining, serial number, SHA-256 fingerprint, and Subject Alternative Names.
3. **Check status** — A color-coded badge shows whether the certificate is valid, expiring soon (under 30 days), or expired.

## FAQ

### What does 'expiring soon' mean?

The certificate is valid but expires within 30 days. Most certificate authorities recommend renewing at least 30 days before expiry to avoid downtime.

### What are SANs?

Subject Alternative Names — additional domain names covered by the certificate. For example, a cert for example.com might also cover www.example.com and api.example.com.

### Can I check any domain?

Any publicly accessible domain with HTTPS on port 443. Internal or non-standard port certificates can't be checked.

### What protocol and cipher are shown?

The TLS protocol version (e.g. TLSv1.3) and cipher suite (e.g. TLS_AES_256_GCM_SHA384) negotiated during the connection. These indicate the encryption strength. For checking CORS and other headers, try the [CORS tester](https://varstatt.com/toolkit/cors-tester).

## Usage

This tool runs entirely in the browser — visit the URL above to use it.

Prefill inputs via URL parameters:

- `https://varstatt.com/toolkit/ssl?hostname=...`

## Related Tools

- [DNS](https://varstatt.com/toolkit/dns)
- [SSL](https://varstatt.com/toolkit/ssl)
- [CORS](https://varstatt.com/toolkit/cors)