All services

Generate a random EUI-48 MAC address. By default it is locally-administered and unicast (safe for testing); set `local:false` for a universal-bit address or `multicast:true` for a group address.

Given an emoji character (or any string), return its code points and — if known — its name, category, shortcodes and tags. An unknown emoji is a successful result with `known:false`, not an error.

Un-project Web Mercator (EPSG:3857) easting/northing in metres back to WGS84 longitude/latitude in degrees.

One's-complement NOT of a non-negative integer within an explicit bit width (two's-complement domain). The value must fit in `width` bits. Returns decimal, hex and binary.

Report the ground resolution (metres per pixel, for 256-px tiles) and the OGC map scale denominator at a zoom level, optionally adjusted for latitude (default equator).

Build a chord from a root note and quality (major, minor, dim, aug, maj7, min7, dom7, dim7, half-dim7, sus2, sus4, maj6, min6). Notes are spelled by stacked thirds (C dom7 → C E G Bb). Returns the note names, MIDI numbers and semitone intervals.

Parse an ISO 8601 duration such as 'P1Y2M10DT2H30M' into its components. Returns a normalized ISO string and totalSeconds — but totalSeconds is null when the duration contains years or months, because those are calendar-variable (use /v1/add or /v1/between for exact date math).

Convert a decimal string to an exact reduced fraction. For a repeating decimal, set repeat to the number of trailing fractional digits that repeat (e.g. value='0.1666', repeat=1 → 1/6; value='0.3', repeat=1 → 1/3). A non-numeric value is a clean 400.

Compute the standard English readability formulas — Flesch Reading Ease, Flesch–Kincaid grade, Gunning fog, SMOG, Coleman–Liau and ARI — along with the underlying sentence/word/syllable statistics. Empty text is a clean 400.

Two directions over query strings. action='parse' decodes a query string (with or without a leading '?') into an object, collapsing repeated keys into arrays. action='build' encodes a params object into a query string, expanding array values into repeated keys; set sort=true to order keys alphabetically.

Validate a number by the Luhn (mod-10) algorithm — the scheme behind credit/debit card numbers and many IDs. Spaces and hyphens are ignored. A mismatched check digit is a successful { valid: false }.

Adler-32 checksum (as used by zlib) over the input payload. Faster than CRC-32 but weaker for short inputs. Returns the checksum as an unsigned integer and 8-digit hex. Non-cryptographic.

Break a string into its Unicode code points, each with its U+ notation, decimal value and UTF-8 / UTF-16 byte layout, plus total byte lengths.

Report the ground resolution (metres per pixel, for 256-px tiles) and the OGC map scale denominator at a zoom level, optionally adjusted for latitude (default equator).

Validate an ISBN-10 (mod-11, trailing X allowed) or ISBN-13 (GTIN mod-10) book number. Length after removing spaces/hyphens selects the scheme.

Validate a payment-card number: Luhn check-digit test plus network detection and length check. A syntactically valid number that fails Luhn returns `valid:false` (a 200, not an error).

Generate a harmony scheme (complementary, analogous, triadic, tetradic, monochromatic) from a base color.

Build braille cells from raised-dot numbers (each cell an array of 1–8). Out-of-range or repeated dots are clean 400s.

Render an ISO 8601 duration as an English phrase, e.g. 'P1Y2M' → '1 year and 2 months'. Components are shown in descending order with correct pluralization.

Transcribe text to Unicode braille (grade-1 / uncontracted English braille), with capital and number signs. Characters with no grade-1 representation are clean 400s.

Project WGS84 longitude/latitude (degrees) to Web Mercator (EPSG:3857) easting/northing in metres. Latitude is clamped to ±85.0511° (the projection's valid extent).

Estimate password strength: score, guesses, crack-time and feedback. Never stored.

Split YAML front-matter from a document — returns the parsed metadata object and the remaining content body. Malformed YAML is rejected as a clean 400.

List every ISO 3166-1 alpha-2 country code for which a postal-code pattern is available.