Cookie Security Checker

Audit a site's cookies

SSL Certificate Checker

Inspect an SSL certificate

Security Headers Checker

Score a site's security headers

MX Record Checker

MX record lookup

DMARC Checker

Check a domain's DMARC

DKIM Checker

Check a DKIM selector

Find the selector in an email header's DKIM-Signature: s=... field.

SPF Checker

Check a domain's SPF

DNS Lookup

DNS records

WHOIS Lookup

WHOIS / RDAP lookup

JWT Decoder

Decode a JWT

Privacy: runs entirely in your browser. We do not verify the signature (that needs the secret key).