SSL CheckerWEBTOOLSHUB
Built by Konko Maji

Check any site's SSL certificate

Issuer, expiry date, days remaining, Subject Alternative Names, TLS version and validity. Free, instant, no signup.

Enter a hostname (no https:// needed). Reads the live certificate on port 443.

Inspect any certificate.

Enter a hostname above to read its SSL/TLS certificate.

Valid Invalid / expired
Check the DNS too

A, AAAA, MX, NS, TXT, SOA and CAA records for any domain.

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POWER USER?

WebToolsHub CLI

The ssl command reads the live certificate and reports issuer, expiry, days left, SAN and the negotiated TLS version.

# human readable
python cli.py ssl github.com

# full JSON, custom port
python cli.py ssl github.com --port 443 --json
THE BIG DIFFERENCE

Check certificates from inside your AI

This tool speaks the Model Context Protocol (MCP) and ships a REST API. Connect it once, then ask your assistant whether a site's certificate is valid or when it expires.

Claude ChatGPT Gemini Kimi Cursor
See the connection guide

What is an SSL checker?

An SSL checker connects to a website over HTTPS and reads its SSL/TLS certificate, then reports who issued it, which hostnames it covers, when it expires, the TLS version negotiated, and whether it is currently valid for the host. It is the fastest way to confirm HTTPS is set up correctly and to catch a certificate before it expires.

What each field means

How to check an SSL certificate

  1. Enter the site's hostname (for example github.com).
  2. Select Check. The certificate details appear in a couple of seconds.
  3. Read the status, issuer and the days remaining before expiry.
  4. Use the CLI or the MCP and REST connectors to automate certificate monitoring.

Why this tool needs a server

Reading a raw TLS certificate needs a direct socket to port 443, which browsers do not expose to web pages. The hosted version performs the check on the server, and the identical check is available in the command line and over MCP and the REST API, so it works from your terminal and inside AI assistants too.

Frequently asked questions

What is an SSL checker?

An SSL checker connects to a website over HTTPS and reads its SSL/TLS certificate, then reports the issuer, the common name and Subject Alternative Names, when the certificate was issued and when it expires, how many days remain, the negotiated TLS version and cipher, and whether the certificate is currently valid for the host.

How do I check when an SSL certificate expires?

Enter the site's hostname and the tool shows the certificate's valid-until date and the number of days remaining, flagging certificates that have expired or are expiring soon.

Is the SSL checker free and open source?

Yes. It is completely free and open source under the MIT license, part of WebToolsHub by Konko Maji. It reads the live certificate over a TLS connection. There is no signup and no data is stored.

Why does the SSL checker need a server?

Reading a raw TLS certificate requires a direct socket connection to port 443, which browsers do not expose to web pages. The hosted version runs the check on the server, and the same check is available in the CLI and over MCP and the REST API.

Can I run an SSL check inside Claude, ChatGPT or Gemini?

Yes. It ships an MCP server and a REST API, so you can connect it to Claude, ChatGPT, Gemini, Kimi, Cursor and any MCP client, then ask your assistant to check a site's certificate and expiry for you. See the connection guide.