[ dev ]

a mini postman: any method, headers, body, auth — see status, headers, timing

fire a JSON payload at a URL N times, optionally HMAC-signed

every hop, status and header until the final URL

fetch a URL and grade its security headers

A/AAAA/CNAME/MX/TXT/NS/CAA/SOA/SRV across 4 resolvers (propagation)

chain, expiry, SANs, protocol and cipher of any HTTPS host

registration data for a domain or IP

ASN, network and location for an IP

network, broadcast, ranges and host counts (v4 + v6)

is a TCP port open on a public host

turn a curl command into fetch, python, go or httpie

browser, os, device and bot detection for any UA string

format, validate, minify, tree view, JSONPath query

structural diff of two JSON documents

convert between data formats

encode and decode, text or files

percent-encoding and a URL dissector

escape and unescape

code points, names-ish, invisible and look-alike characters

decode, verify (HS/RS/ES) and watch expiry

md5, sha-1/2/3, blake2, hmac — text or file

generate v4/v7, ulid, nanoid; decode timestamps

unix s/ms/µs ⇄ iso ⇄ human, many time zones

javascript and python flavours with live highlighting

plain-english cron + next 10 runs

line and word diff of two texts

camel, snake, kebab, title, slugify

chars, words, lines, bytes, reading time

sort, unique, reverse, shuffle, trim

render markdown exactly as s1d does

placeholder text

names, emails, addresses, uuids as JSON or CSV

generate (svg/png) and decode from an image or camera

random passwords and diceware passphrases with entropy

convert hex/rgb/hsl/oklch, WCAG contrast checker, gradients

bin/oct/dec/hex, bitwise ops, two's complement

rwx ⇄ octal ⇄ symbolic

compare hours across cities

resize, convert and compress images in your browser