Every check in one place. Filter by category or search by name.
Query any DNS record type for a domain.
Resolve IPv4 (A) records for a hostname.
Resolve IPv6 (AAAA) records for a hostname.
List mail exchangers and their priorities.
List the authoritative name servers.
Read TXT records including SPF and verification tokens.
Follow canonical name aliases.
Inspect the Start of Authority record.
Resolve service (SRV) records.
See which CAs may issue certificates.
Resolve an IP address back to a hostname.
Fetch and parse a domain's SPF record.
Retrieve a DKIM public key by selector.
Read and interpret a DMARC policy.
Build a valid DMARC record interactively.
Check for a BIMI brand logo record.
Score mail-server configuration and reachability.
Connect to a mail server and read its banner.
Parse raw headers into a delivery timeline.
Geolocation, ASN and network owner for an IP.
Look up an autonomous system number.
Measure round-trip latency to a host.
Check common TCP ports on a host.
Approximate the location of an IP address.
Validate a site's certificate and chain.
Count the days left on a certificate.
Decode a PEM certificate into readable fields.
Registration, registrar and nameserver details.
How long a domain has been registered.
Test an IP or domain against DNSBLs.
Aggregate DNS, email and SSL into one score.
Inspect response headers for a URL.
Grade a site's HTTP security headers.
Check whether a site is up and how fast.
Fetch and summarise a site's robots.txt.
Encode or decode Base64 text instantly.
Compute MD5, SHA-1 and SHA-256 digests.
Percent-encode or decode URL components.
Validate and pretty-print JSON.
Compute network, broadcast and host ranges.
Create strong, random passwords.
Convert between Unix time and dates.