Free sysadmin tools that run entirely in your browser — no signup, no data leaves your machine. Built for the kind of work we write about here.
CIDR CalculatorIP range, netmask, broadcast, usable hosts and binary — from any address/prefix.
Epoch ConverterUnix timestamps to human dates and back, UTC and local time.
Cron ExplainerPaste a cron expression, get plain English. Supports ranges, steps and lists.
Base64 Encode / DecodeUTF-8 safe encoder and decoder, with URL-safe variant.
chmod CalculatorTick the permission boxes, get the octal mode and symbolic form.
DNS LookupA, AAAA, CNAME, MX, TXT and NS records for any domain, via DNS-over-HTTPS.
SSL CheckerLive TLS certificate check: issuer, validity dates and days until expiry.
Password GeneratorStrong random passwords generated locally with the Web Crypto API.
Website Speed TestResponse time from your browser and from our server: DNS, TLS and TTFB breakdown.