Small utilities for DNS, TLS, headers, and day-to-day troubleshooting. Each tool opens on its own page.
CIDR, network/broadcast addresses, usable host range, and wildcard mask.
Cryptographically random passwords with length and charset options.
Common TCP/UDP ports and typical services.
Lookup location, ISP, and ASN via ipapi.co.
TLS certificate validity, issuer, SANs, and key details.
Parse headers for SPF, DKIM, DMARC, routing, and metadata.
Query A, AAAA, MX, TXT, NS, CNAME, and more.
Reference table of common HTTP status codes.
PTR records for IPv4 and IPv6 addresses.
Decode a Windows Autopilot hardware hash to inspect embedded device metadata.
Build a v=spf1 TXT line from IPs, includes, and policy.
Encode files to Base64 or decode Base64 to a downloadable file.
Convert between YAML and JSON in the browser.
JavaScript RegExp tester with matches and replacement preview.
Map extensions to MIME types and back.
Create a QR image from text or a URL and download PNG.
OUI vendor hint from a device MAC address.
Length, mass, volume, and temperature conversions.
Build a DMARC TXT record with policy, reporting, and alignment options.
Convert between Unix epoch and local/UTC date-times.
Decode JWT header and payload (no signature verification).
SHA-256, SHA-1, SHA-512, and MD5 hashes of text or files.
Human-readable summary and next UTC run times for 5-field cron.
Bulk UUIDv4 generation with Windows GUID formatting options.
Pretty-print, minify, and validate JSON payloads.
encodeURI / encodeURIComponent helpers for query strings and OData.
Test whether an IPv4 address falls inside a CIDR range.
Inspect subject, SANs, dates, and fingerprints from a cert PEM.
Domain and IP registration data via RDAP.
Check an IPv4 address against common DNS blocklists.