DNS Lookup
DNS Propagation Check

Query multiple public resolvers worldwide via DNS-over-HTTPS to check if your record has propagated.

MX Lookup — Mail Exchangers
TXT / SPF / DMARC Lookup

Looks up TXT records plus checks _dmarc.{domain} automatically.

NS Lookup — Nameservers & SOA
Reverse DNS (PTR) Lookup
Domain WHOIS

Looks up domain registration data via the RDAP protocol (successor to WHOIS, returns structured JSON).

IP / ASN WHOIS
Your Public IP Address
Detecting…
IP Geolocation
Subnet / CIDR Calculator
Reverse DNS (PTR)
HTTP Response Headers

Fetches a URL and shows response headers. Requires the server to send CORS headers — most APIs and CDNs do. Private or same-origin-only sites will be blocked.

SSL / TLS Certificate Checker

Full TLS analysis via Qualys SSL Labs. First-time analysis takes 30–90 s; cached results return instantly.

Certificate Transparency Log Search

Search crt.sh for all certificates ever issued for a domain. Useful for finding sub-domains and monitoring issuance.

CSR Decoder

Paste a PEM-encoded Certificate Signing Request (starts with -----BEGIN CERTIFICATE REQUEST-----) to decode and verify its contents before submitting to a CA.

Certificate Decoder

Paste a PEM-encoded SSL certificate (starts with -----BEGIN CERTIFICATE-----) to decode and view all its fields.

Certificate Key Matcher

Check whether your private key matches your SSL certificate by comparing their public key moduli. Paste both below — nothing is sent to any server, all processing is done in your browser.

Certificate (PEM)
Private Key (PEM)