Free Online SSL Certificate Inspector & HTTPS Checker - ATools

Free online SSL certificate inspector & HTTPS checker: In-depth X.509 certificate parsing (issuer/validity/SAN), domain HTTPS reachability tests, and direct access to authoritative audit reports.

View source on GitHub

Note: In-browser sandboxes cannot directly intercept raw TLS handshake certificates from external sites. This tool provides: ① Online domain HTTPS reachability & redirect testing with direct links to authoritative reports; ② Instant, local client-side parsing of SSL certificate files (.crt/.cer/.pem) for detailed fields and expiration countdowns.

Domain & URL Input

Authoritative SSL Security Reports

For complete certificate chain validation, cipher suite ratings, and OCSP stapling audits:

Qualys SSL Labs Deep Audit MySSL Security Rating crt.sh Certificate Transparency Logs

HTTPS Connectivity Results

Enter domain and click “Check Domain”