Free domain and network tools
Check any domain's SSL certificate, DNS propagation, mail blocklists, and subdomains. Free, no account, results in seconds. Enter a domain to get started.
DNS Lookup
All records - A, AAAA, MX, NS, TXT, SOA, CAA, SRV - with TTLs and DNSSEC.
Open tool →SSL/TLS Checker
Certificate issuer, expiry, SAN, negotiated protocol and supported TLS versions.
Open tool →Security Headers
Grade a site's HTTP security headers A-F, with a fix for each missing one.
Open tool →DNS Propagation
Compare a record across 8 public resolvers worldwide to spot propagation lag.
Open tool →Blacklist (RBL)
Check the domain and its IPs against major mail blocklists like Spamhaus.
Open tool →Redirect Checker
Trace the HTTP redirect chain and catch loops and HTTPS downgrades.
Open tool →Subdomain Finder
Discover live subdomains by probing common labels via DNS.
Open tool →Reverse IP Lookup
Find other domains in our index that resolve to the same IP address.
Open tool →Bulk Domain Checker
Check many domains at once - which resolve and which accept mail.
Open tool →Punycode & IDN Converter
Convert Unicode and xn-- forms and detect homograph / look-alike domains.
Open tool →CSP & HSTS Analyzer
Break down Content-Security-Policy directives and check HSTS preload eligibility.
Open tool →Email Tools →
SPF, DMARC, DKIM, MX, BIMI, MTA-STS, TLS-RPT and raw header analysis.
Open section →Free JSON API
Every tool as a no-key JSON endpoint - domain report, SSL, DNS, blacklist, subdomains.
Read the docs →Everything runs on our own infrastructure
These tools query the target host and public DNS directly - there are no third-party API keys, accounts, or rate-limited services in the way. The SSL checker opens a real TLS handshake to the domain, the propagation tool asks several independent public resolvers the same question, and the blacklist checker looks the domain's IPs up in well-known DNS blocklists. For a complete picture of a single domain, open its full report.