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SSL Certificate Checker
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Free online SSL certificate checker. Verify website SSL validity, view issuer details, and check expiration dates instantly.
Supports domain names, URLs with protocols, or host:port format. Default port is 443.
The full scan covers protocols, cipher suites, certificate details, and common vulnerabilities. Focused scans check one category; cipher enumeration can still take several minutes.
Active TLS checks send multiple probes. Scan only systems you own or are authorized to assess.
Overview
Understand what the tool solves, how it works, and the boundaries of its data.
Enter a publicly reachable HTTPS host to inspect the certificate presented for that connection. The certificate summary includes its subject and issuer, validity start and end dates, remaining days, hostname match, and certificate-chain information; connection details may include the negotiated protocol and cipher. A certificate’s validity period is the interval during which it is intended to be valid. The Internet X.509 certificate profile defines certificate validity fields and names (RFC 5280, checked 2026-09-29).
A certificate may be within its date range yet fail to match the hostname you entered. The checker reports a hostname match and authorization status for the observed connection. Chain information describes the certificates presented along the path; successful validation depends on trust and verification rules, not merely on seeing an issuer name. A successful certificate check does not establish that the website’s content or overall security is safe.
The connection is checked when you submit the host. Certificate replacement, DNS routing, server configuration, network location and time can affect what a later check observes. Use the displayed checked time and host to interpret the result; repeat the check after a change if you need to confirm the new presentation.
Guide
Follow the workflow and verify inputs and outputs with practical examples.
Enter the host name you want to check, without relying on a different hostname such as a separate www subdomain.
Start the certificate check and wait for the connection result.
Review the host and port, validity dates, days remaining, issuer, hostname match and authorization status together.
If a mismatch or validation error appears, verify the exact hostname and review the certificate deployment and chain with your administrator.
Repeat after a fix to confirm what the server presents at that time.
Use cases
See how the tool fits into real work and everyday tasks.
Check the expiration date for a host you manage, then compare it with your renewal schedule and monitor again after renewal.
Check the exact host users visit; the apex domain and a subdomain can present different certificate coverage.
After updating a certificate or chain, run another check to see the connection’s newly presented details.
Q&A
Find concise answers to common questions and confusing cases.
No. This check reports certificate and connection details; it is not a full review of a site’s code, content, account security or vulnerabilities.
The certificate may not cover the exact host name, or the connection may fail another chain or trust check. Review the hostname and authorization result rather than relying only on the end date.
The server may have changed certificates or routing, or the later connection may reach a different endpoint. Treat each result as an observation at its displayed check time.
Notes
Review scope, result limitations, and important precautions before use.
This is a connection-level observation of the host entered. It does not guarantee the same certificate will be served to every visitor or from every network, and it does not grade overall website security. If you do not administer the host, use results for troubleshooting and contact its operator before making changes.
Related
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