The webmaster & sysadmin toolbox

Domain WHOIS Ownership, registrar & expiry for any domain. DNS Lookup A, AAAA, MX, TXT, NS, CNAME & SOA records. Reverse DNS / PTR Resolve an IP back to its hostname.

IP Lookup Geolocation, ISP & ASN for any IP address. HTTP Header Checker Inspect response headers, status & redirects. Port Checker Test if common or custom ports are open. Website Up / Down Check if a site is online and its response time.

SSL Certificate Checker Issuer, validity, expiry & SANs of any HTTPS site. HTTP Security Headers Grade a site’s security headers (HSTS, CSP & more). Blacklist Checker See if an IP is on common spam blacklists. Password Generator Strong, configurable passwords — generated in-browser.

Hash Generator MD5, SHA-1, SHA-256 & more, instantly. Base64 Encode / Decode Convert text to and from Base64. Subnet / CIDR Calculator Network, broadcast, mask & host range. JWT Decoder Decode and inspect JSON Web Token claims. Cron Expression Helper Translate cron syntax to plain English. UUID Generator Generate v4 UUIDs in bulk, instantly.