Web & DNS

Look up the postal PIN code for an Indian address.

Generate a favicon from an image, or check an existing site's favicon.

Look up a domain's DNS records.

Check whether a domain name is available to register.

Look up the location and details behind an IP address.

Look up the registration details of a domain.

Check a site's SSL certificate and expiry date.

Check how quickly a website responds.

Shorten a long URL, or expand a shortened one to see where it leads.

Break any URL down into its protocol, host, path and query parameters.

Check a page's title, description and Open Graph preview.

Pull the colour palette used on any website from a screenshot.

Find the IPv4 addresses a domain name points to.

Find the IPv6 addresses a domain name points to.

See which mail servers receive email for a domain, in priority order.

Read a domain's TXT records, including SPF, DKIM and verification entries.

Find where a domain's CNAME alias points to.

Find a domain's authoritative name servers.

Find the hostname (PTR record) behind an IPv4 or IPv6 address.

Check whether a DNS change has spread, by asking six public resolvers (Google, Cloudflare, Quad9, OpenDNS, Verisign, AdGuard).

Work out the network, netmask, broadcast, usable host range and host count for any IPv4 CIDR block, and split it into smaller subnets.

Look up an IPv4 address's type (private, public, loopback), class, decimal, hex and binary forms, and reverse DNS name.

Expand, compress and analyse an IPv6 address: type, network range for a prefix, address count and reverse DNS name.

Convert between a CIDR prefix like /24 and a subnet mask like 255.255.255.0, with wildcard mask, binary and host counts.

Turn a start and end IP address into the smallest list of CIDR blocks that covers it exactly.

Search common TCP and UDP port numbers and the services that use them — 22 SSH, 443 HTTPS, 5432 PostgreSQL and more.

Paste a response's headers and get a security review: HSTS, CSP, cookies, clickjacking, CORS and information leaks.

Check when a website's SSL certificate expires and who issued it, so it never lapses unnoticed.