Network tools
DNS, whois, SSL, headers and other lookups.
DNS Lookup
Look up every DNS record type for a domain in one query: A, AAAA, MX, TXT, NS, CNAME, SOA and CAA. Free online DNS checker.
Hostname to IP
Resolve a hostname to every IPv4 and IPv6 address it points to, and see which CDN or host answers. Free online DNS resolution.
IP to Hostname
Run a reverse DNS lookup on any public IP address and see the PTR records it resolves to. Free online reverse IP checker.
Whois Lookup
Look up whois data for any domain: registrar, creation and expiry dates, status codes and name servers, with the raw response included.
SSL Checker
Check a TLS certificate: issuer, validity dates, days until expiry, covered host names, protocol, cipher and the full chain. Free online SSL checker.
HTTP Header Checker
Fetch any URL and read every HTTP response header, with security headers, caching and compression called out. Free online header checker.
HTTP Status Checker
Check the HTTP status code any URL returns, with the meaning explained and the full redirect chain shown. Free online status checker.
Website Status Checker
Check whether a website is up from outside your network, with status code, response time, TLS details and server headers. Free online uptime check.
Redirect Checker
Follow a URL through every redirect and see each hop with its status code, target and timing. Detects loops and mixed http hops. Free.
URL Unshortener
Expand a shortened link and see the full destination before you visit it, including every hop along the way. Free and safe to use.
Compression Test
Check whether a URL is served compressed, which algorithm is used, and how many bytes compression saves. Free online gzip and brotli test.
Ping Test
Measure round trip time to any public host from our server, with four samples, best, worst and average. Free online latency test.
Port Checker
Check whether specific ports are reachable on a host from outside your network. Up to ten ports per check, with the usual service named.
SMTP Test
Connect to a mail server and read its greeting and advertised capabilities, including STARTTLS, AUTH and message size limit. Free SMTP check.
Page Source Viewer
Fetch the raw HTML a server returns for any URL, before JavaScript runs. See what crawlers see. Free online source viewer.
What Is My IP
See the public IP address your connection presents to websites, with reverse DNS and the request details your browser sends. Free.
IP Information
Look up any public IP address: registry data on the owning network, allocation range, reverse DNS and address type. Free IP lookup.