Check a host over HTTPS from your browser — SSL/TLS reachability (which proves the browser validated the certificate chain) plus public issuance history (issuer, expiry, cert count) via crt.sh. No cipher-suite or protocol-version scan: browsers do not expose handshakes.
Content reviewed October 2026 · About Toolzum
Check SSL/TLS certificate details for any domain via public certificate APIs. View issuer, validity period, days remaining, and SANs. Expiry alerts catch outages before users do — free, no signup.
Discover subdomains via public certificate records plus live DNS checks of common names. Read-only lookups run from your browser — the domain you check is visible to crt.sh and Google DNS, as with any lookup.
Run an HTTP security probe on a live URL — reachability, redirect chain, and visible response details, plus a reference checklist for HSTS, X-Frame-Options, and CSP.
Count characters, letters, digits, spaces, and punctuation as you type — totals with and without spaces plus an upper/lowercase split. Fit a 280-character post exactly — free, local, no signup.
Analyzes your writing with real-time word count, character counts with and without spaces, sentence and paragraph counts, plus estimated reading time (200 wpm) and speaking time (150 wpm). Essential for writers, students, and SEO professionals tracking length and pacing.
HTTPS reachability (browser-validated chain) plus crt.sh issuance history: issuer, expiry dates, and cert count. No cipher suites or protocol versions.
None are flagged — the tool reports reachability and history only. For weak-cipher grading, look up suite names in the TLS Cipher Checker.
Reachability probes the target host and history queries crt.sh — both requests leave the browser by design. Results only, nothing stored to an account.
The hostname is sent to the probed host and to crt.sh to fetch history; free with no signup, nothing saved to an account.
SSL Certificate Decoder
Decode and view SSL certificate details including subject, issuer, and validity period. Code never leaves your device — formatting and validation run locally in your browser.
SSL Checker
Check SSL/TLS certificate details for any domain via public certificate APIs. View issuer, validity period, days remaining, and SANs. Expiry alerts catch outages before users do — free, no signup.