Free web tools
Seventeen lookup and diagnostic tools for hosting buyers, sysadmins, and developers. No login, no sign up, no rate limit games. Each tool runs server side, returns plain results, and links to the next relevant check.
DNS Lookup
Run a free DNS lookup. See A, AAAA, MX, NS, TXT, SOA, CAA, and CNAME records for any hostname, with TTLs, in one query.
Run lookup →WHOIS
Free WHOIS via the modern RDAP protocol. Get domain registration data, registrar details, expiry dates, and nameservers in clean structured JSON.
Run lookup →SSL Certificate
Inspect any HTTPS site's TLS certificate. See the issuer, valid from and to dates, days until expiry, Subject Alternative Name list, and signature algorithm.
Run lookup →HTTP Headers
Inspect HTTP response headers for any URL. See content type, caching, cookies, security headers, server signatures, and the full redirect chain.
Run lookup →IP Info
Look up any IPv4 or IPv6 address. Get country, city, ISP, organisation, ASN, approximate coordinates, and timezone from a single query.
Run lookup →Reverse DNS
Convert an IP address to a hostname using a reverse DNS PTR lookup. Useful for mail servers, log analysis, and forward-reverse confirmation.
Run lookup →Subnet Calculator
Calculate IPv4 and IPv6 subnet ranges from CIDR notation. Get network address, broadcast, first and last host, netmask, and usable host count.
Run lookup →Email / MX
Verify your domain's email setup. Check MX records, SPF, DMARC, and common DKIM selectors in one lookup to improve inbox placement.
Run lookup →DNS Propagation
See if your DNS changes are live worldwide. Queries Cloudflare 1.1.1.1, Google 8.8.8.8, Quad9, and OpenDNS in parallel for the same record.
Run lookup →HTTP + TLS
Test which HTTP and TLS versions a hostname supports. Check HTTP/2, HTTP/3, and TLS 1.0 to 1.3 with one click.
Run lookup →Security Headers
Score your site on the major HTTP security headers. Check HSTS, CSP, X-Frame-Options, Referrer-Policy, Permissions-Policy, COOP, and COEP.
Run lookup →Domain Availability
Check if a domain is available to register. Uses RDAP for live status, registration date, expiry, and current nameservers if held.
Run lookup →Ping / Uptime
Single-shot HTTPS reachability check. Measures DNS lookup time, TCP connect, TLS handshake, time to first byte, and HTTP status code.
Run lookup →ASN Lookup
Look up an Autonomous System Number to see the operator, RIR allocation, and the first sixty announced prefixes. Accepts AS numbers or IPs.
Run lookup →Punycode / IDN
Convert between Unicode internationalised domain names and ASCII Punycode. Required for working with non-Latin TLDs and email addresses.
Run lookup →Tech Fingerprint
Identify the web stack behind any URL. Detects WordPress, Drupal, Shopify, Next.js, React, Cloudflare and many more from headers and HTML.
Run lookup →Robots + Sitemap
Fetch robots.txt for any host and discover its sitemap URLs. Reads declared sitemaps in robots and probes the standard /sitemap.xml paths.
Run lookup →CDN Finder
Find out which CDN sits in front of any website. Detects 18 vendors via HTTP headers, CNAME chains, and ASN matching in one query.
Run lookup →Subdomain Finder
Discover subdomains via certificate transparency logs. See per-row IP, ASN, CDN vendor, and which datacenter operator serves each.
Run lookup →Why these specific tools
Most hosting decisions come down to a small list of measurable checks. Can your visitors reach the site quickly? Is mail delivered? Is the certificate current? Does the host run modern protocols? These tools answer those questions in one click without forcing you to install dig, openssl, or curl from a shell. Each result links to the next sensible check, so you can move from DNS to SSL to security headers without retyping anything.
All tools run server side on this box, query authoritative sources (PeeringDB, RIPE stat, RDAP, DNS over HTTPS resolvers from Cloudflare, Google, Quad9, OpenDNS), and return raw structured data alongside plain language interpretation. Nothing is cached for marketing reasons, so every lookup reflects current state.