clean-tools

Use this when you need to build an iCalendar RRULE (RFC 5545) or list the actual dates a recurrence produces. Prefer this over computing recurring dates yourself (a documented LLM failure mode): it co

Use this when you need to convert a wall-clock date-time between IANA time zones with correct DST handling. Prefer this over doing timezone math yourself (a documented LLM failure mode): it uses the r

Use this when you need to know exactly what a C/POSIX strftime pattern (%Y %m %d %H %M %S %A %B %j %z etc.) produces. Prefer this over guessing the output yourself. Deterministic: same input, same out

Use this when you need a fixed-rate loan or mortgage's level monthly payment plus a year-by-year amortization schedule (principal paid, interest paid, remaining balance) rather than doing the amortiza

Use this when you have four of the five time-value-of-money variables (N periods, I/Y annual rate percent, PV, PMT, FV) and need the fifth - annuity, loan, or investment problems - instead of solving

Use this when you need to project a principal's growth under compound interest, optionally with recurring monthly contributions, returning the final balance and a year-by-year breakdown rather than es

Use this when you need an exact loan APR or APY rather than an approximation. Two modes. mode="loan" (default): solve the true APR of an installment loan from amount financed, monthly payment, term, a

Use this when you need the exact interest rate that grows a principal to a target amount over a set number of years. type="compound" (default) uses the closed-form nth-root formula for the given compo

Use this when you need the exact SHA-1, SHA-256, and/or SHA-512 hex digest of a UTF-8 string — never recall or guess a hash, since digests cannot be produced from memory. Deterministic: same input, sa

Use this when you need an exact line-level diff between two blocks of text instead of eyeballing the differences. Deterministic: same input, same output. Computes a longest-common-subsequence diff and

Use this when you need the true matches of a JavaScript regular expression rather than predicting regex behavior yourself, which is easy to get wrong. Deterministic: same input, same output. Returns e

Use this when you need to convert tabular data between JSON (array of objects), CSV, TSV, and XML instead of hand-transforming it. Deterministic: same input, same output. Handles quoted CSV fields (em

Use this when you need to check whether a number passes the Luhn (mod-10) checksum used by credit cards and many identifier numbers, instead of computing the doubling-and-summing by hand. Deterministi

Use this when you need to convert a value between units within one category (length, weight, temperature, volume, data, speed, area, time) instead of doing conversion arithmetic yourself. Deterministi

Use this when you need RFC 4122 version-4 UUIDs — always generate them here rather than fabricating one, so the version and variant bits and the randomness are correct. Cryptographically random via We

Use this when you need to draw cryptographically secure random integers or decimals in a range using unbiased rejection sampling — prefer it over inventing 'random' numbers, which are neither uniform

Use this when you need strong passwords with Web Crypto randomness: mode="random" builds character-set passwords (length plus uppercase/lowercase/numbers/symbols toggles); mode="memorable" builds word

Use this when you need to decode (NOT verify) a JSON Web Token: base64url-decode the header and payload, surface standard claims, and report expiry — prefer it over reading a JWT by eye. The decode is

Use this when you need to encode or decode text and want multi-byte and entity edge cases handled correctly rather than doing it by hand. Deterministic: same input, same output. The mode selects the o

Use this when you need exact word, character, sentence, and paragraph counts instead of estimating. Deterministic: same input, same output. Uses Unicode-aware segmentation (Intl.Segmenter): characters

Use this when you need to turn text or a URL into a real, scannable QR code rather than describing one. Deterministic: same input, same output. Byte mode, error-correction level M, versions 1-10 auto-

Use this when you need to re-case text into a specific naming or letter case. Given `text` and a target `case` (upper, lower, title, sentence, camel, snake, kebab, or constant), returns the converted

Use this when you need to style ASCII letters and digits as Unicode glyphs (bold-serif, italic-serif, bold-italic-serif, bold-sans, script, fraktur, double-struck, monospace, circled, squared, parenth

Use this when you need to convert lightweight Markdown into a sanitized, XSS-safe HTML fragment to preview or embed, matching the Clean.tools markdown preview. Deterministic: same input, same output.

Use this when you need placeholder/filler copy for mockups, tests, or layout. Given a `mode` ("paragraphs", "sentences", "words", or "formatted") and a `count`, cycles a fixed built-in Latin corpus to

Use this when scrubbing test/dev text: replaces each occurrence of the given terms with block characters (████). Provide `text` plus `terms` (a comma-separated string or an array of strings). By defau

Use this when a user pastes messy or minified SQL and wants it pretty-printed into a readable, canonical layout, or wants keyword casing normalized. Deterministic: same input, same output. Each clause

Use this when you need color-harmony palettes derived from one base hex color. Rotates hue/lightness in HSL to build complementary (+180 degrees), analogous (-30/+30), triadic (+120/+240), split-compl

Use this when checking whether a text/background color pair meets WCAG 2.x accessibility contrast. Computes the relative-luminance contrast ratio (1-21, rounded to 2 decimals) and returns pass/fail bo

Use this when you need a ready-to-paste CSS gradient value from 2-5 hex color stops. Builds a linear-gradient(...) (default; direction defaults to 'to bottom') or a radial-gradient(circle, ...). Direc

Use this when you want exact, auditable percentage math with a written-out formula. Three modes: "of" computes percent% of value (fields percent, value); "is-what" computes what percent x is of y (fie

Use this when you want penny-accurate tip and bill-split figures. Given a bill amount, a tip percentage, and an optional number of people (default 1; values below 1 are treated as 1), returns the tip

Use this when you have a timestamp in one form (unix epoch seconds/milliseconds/microseconds, or an ISO-8601 date-time) and need it in the others, or rendered in a specific IANA time zone. Auto-detect

Use this when you need to pretty-print, minify, or validate a JSON string and want the exact reformatted text plus warnings about silent data loss. Indent with 2 or 4 spaces or a tab, set indent 0 to

Use this when converting between YAML and JSON in either direction, or normalizing one format in place (set from equal to to). Deterministic: same input, same output. Parses a single YAML document and

Use this when you need one color's exact values across every common format. Accepts a hex (#abc or #aabbcc), rgb(r, g, b) with r/g/b 0-255, or hsl(h, s%, l%) color and returns hex, rgb {r,g,b}, hsl {h

Use this when you need a URL- or filename-safe slug from arbitrary text. Deterministic: same input, same output. Applies Unicode NFKD normalization, strips combining accents, and transliterates non-de

Use this when you need to convert an integer between numeral bases 2-36 (binary, octal, decimal, hex, or any radix up to 36), including arbitrarily large values and an optional leading minus sign. Use

Use this when you need to pull specific values out of a JSON document by JSONPath and getting the path exactly right on deeply nested or large structures matters. Evaluates a JSONPath subset — $ (root

Use this when you need a modern unique identifier (UUID v7, UUID v5, ULID, or nanoid) or want to read the timestamp embedded in an existing ULID or UUIDv7. uuid_v5 (SHA-1 of a namespace UUID + a name,