the402 x402 endpoint directory

Convert text between camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, Title Case, lower, UPPER.

Validate, pretty-print, or minify JSON. Returns parse errors with position when invalid.

Mint a stateless captcha challenge to gate your OWN endpoint: returns a human prompt plus a salted sha256 answer hash

Compute the date of Easter Sunday for a given year using the Anonymous Gregorian algorithm (Meeus/Jones/Butcher). Also

Validate CSV structure: consistent column counts across rows, properly closed quotes, delimiter detection. Returns row

Live CLOB orderbook for a Polymarket outcome token. Returns top N bids (highest first), top N asks (lowest first), bes

Live spot price (and optional 24-hour change) for one or more coins from CoinGecko's public Simple Price endpoint. Ide

Return the current USD spot price for an ERC-20 token, identified by its contract address and network. Sourced from Al

Present and future value of a level annuity (equal periodic payments). Supports an ordinary annuity (payments at perio

Compute the internal rate of return (IRR) of a cashflow stream - the discount rate at which NPV = 0. Index 0 is treate

Backtest a forecasting method on the input series by holding out the last `testSize` observations, forecasting them, a

Pearson correlation coefficient between two equal-length numeric series. Returns r (the correlation, -1 to 1), r² (var

Enumerate every <a href> in an HTML string with its anchor text and rel attribute. Optionally resolves relative hrefs

Fetch and validate a domain's DMARC policy at _dmarc.<domain> (RFC 7489). Surfaces the enforcement policy (none/quaran

Resolve an ENS name (e.g. vitalik.eth) to its Ethereum address - so an agent can turn a human-readable recipient into

Resolve an RFC 6901 JSON Pointer (e.g. /items/0/name) against a JSON value. Returns the value or found:false.

Format a timestamp as a human relative phrase ("3 hours ago", "in 2 days") versus now or a reference time.

Percentage helper. op: "of" (a% of b), "change" (% change a→b), "ratio" (a is what % of b).

Convert an integer between number bases (radix 2-36), e.g. binary↔hex↔decimal. Arbitrary size via BigInt.

Levenshtein edit distance between two strings, plus a 0-1 similarity ratio.

Count characters, words, lines, and (optionally) occurrences of a substring in text.

CRC-32 checksum of a text string (hex), the IEEE polynomial used by zip/png/gzip.

Inspect the TLS certificate of any public host: subject, issuer, validity window, days remaining, SANs, and SHA-256 fi

Parse a semantic version, or compare two (a vs b → -1/0/1, with greater/lesser flags).

Difference between two dates/times in ms, seconds, minutes, hours, days, and a human summary.

Turn any text into a URL-safe slug (lowercase, hyphenated, diacritics stripped).

Decode a JWT without verification: header, payload, expiry status, and time remaining. (Decoding only - signatures are

HMAC signature of a message with a shared key. Algorithms: sha256 (default), sha512, sha1. Returns hex and base64.

Generate a single-use Coinbase Onramp URL that lets a human fund any wallet with a card or Apple Pay - the fastest way

Check whether a year is a leap year and get related info: days in that year, the next and previous leap years, and the

Compute Flesch-Kincaid Grade Level, Flesch Reading Ease, Gunning Fog Index, and Automated Readability Index from text.

Top DEX pools (Uniswap, Sushi, Curve, Aerodrome, etc.) ranked by current TVL - filterable by chain and project. Source

Resolve an ERC-20 contract address to its on-chain metadata: symbol, decimals, name, and logo URL where available. Use

Risk-adjusted return: (mean return - risk-free rate) / sample standard deviation of returns (n-1). Pass periodsPerYear

Compute the net present value of a stream of cashflows at a given discount rate. Index 0 is treated as t=0 (today, not

Holt-Winters triple exponential smoothing - level + trend + seasonal component. Use for series with a repeating cycle

Flag outliers in a numeric series using either the IQR rule (Tukey fences at 1.5·IQR - robust, default) or z-score (|z

Compute the full descriptive-stats panel for an array of numbers in one call: count, sum, mean, median, mode, stddev (

Decompress a base64-encoded gzip payload. Returns the result as utf8 (text) or base64 (binary). Refuses to expand past

Strip all HTML tags and return plain text. Preserves block-level structure (paragraphs and headings become newline-sep

Fetch and validate a domain's SPF record (RFC 7208). Parses mechanisms (ip4/ip6/include/a/mx/all), counts DNS lookups

Check the confirmation status of a transaction by hash on Base/Polygon/Arbitrum/Optimism/Ethereum/Monad/Celo/Avalanche

Score a password's strength: character-set size, entropy bits, a 0–4 rating, and an estimated offline crack time. The

Compute a precise age (years, months, days) from a birth date to today (or a given date), plus total days.

Convert a value between units of length, mass, temperature, volume, area, speed, time, data, pressure, energy, power,

Parse a URL query string into an object, or build one from an object. mode: parse (default) | build.

Remove duplicate lines, preserving first-seen order. Returns the deduped text and how many were removed.

Validate a payment card number (Luhn checksum) and detect the brand. Numbers are not stored or logged.

Parse a duration like "2h30m" / "1d4h" / "90s" to seconds, or humanize a number of seconds.

Run a regular expression against text. Returns up to 100 matches with index and capture groups. Pattern ≤ 200 chars, t