Free Webmaster Tools

Free, no-signup tools for DNS, WHOIS, SSL, HTTP headers and email deliverability. Every result is a live lookup — nothing here is canned or cached from someone else.

DNS & Domain 8

DNS Lookup

Query any DNS record type for a domain

DNS Propagation Checker

See what resolvers around the world return

Domain to IP

Resolve a domain to its IPv4 and IPv6 addresses

WHOIS Lookup

Registrar, dates and nameservers for a domain

DNSSEC Checker

Is the domain signed, and does it validate?

IP Address Lookup

Network, ASN and reverse DNS for any IP

BGP Upstream Checker

See which transit providers actually carry a prefix

IPv6 Compatibility Test

Does your site actually work over IPv6?

Security 5

SSL Certificate Checker

Issuer, expiry, chain and hostname match

Origin Exposure Checker

Is your real server IP leaking past your CDN?

Security Headers

Grade a site's HTTP security headers

Mixed Content Checker

Find insecure resources on an HTTPS page

CORS Checker

Test cross-origin headers and preflight behaviour

HTTP & Performance 5

Website Status Checker

Is it up? Status code, redirects and timing

HTTP Header Checker

Response headers, caching and CDN detection

CDN Detector

Find out which CDN is in front of a site

Redirect Checker

Trace every hop in a redirect chain

HTTP/2 & HTTP/3 Test

Which modern protocols does a site support?

SEO 4

Robots & Sitemap Tester

Validate robots.txt and your XML sitemap

Meta Tags Checker

Title, description, canonical and social tags

Schema Markup Validator

Check JSON-LD structured data for errors

Favicon Checker

Find every icon a site declares and test it loads

Email 3

MX Record Checker

Check a domain's mail routing

Blacklist Checker

Is your mail server on a DNS blocklist?

SPF, DKIM & DMARC Checker

Check a domain's email authentication

Media & Utilities 4

HLS & DASH Stream Checker

Validate a video manifest and its renditions
In browser

User Agent Parser

See your own user agent, or break down any string
In browser

URL Encoder / Decoder

Percent-encode and decode text safely
In browser

URL Parser

Split a URL into its component parts

Network Diagnostics 3

Looking glass

Ping

Round-trip latency and packet loss from our cloud locations
Looking glass

Traceroute

Every hop between our network and any host, mapped
Looking glass

MTR

Per-hop loss and latency over repeated cycles

About these tools

Every tool here performs a real lookup when you press the button — a DNS query to a public resolver, a WHOIS request to the registry, a TLS handshake, an HTTP request. Nothing is canned and nothing is pre-recorded.

We do not store what you look up. There is no account, no signup and no rate card. The two URL utilities never contact us at all; they run entirely inside your browser.

They exist because we run CDNShark — a global CDN with edge delivery, DNS, VPS and hosting — and these are the checks our own team reaches for every day.