api.24klabs.ai publishes 61 machine-payable endpoints over the x402 protocol, priced from $0.001 to $0.006 per call. Each was probed directly; the response code below is what it returned.
European call/put fair value plus delta, gamma, theta, vega, rho from spot, strike, days-to-expiry, rate and volatility; optional implied-vol solve if market_price supplied.
Clean price or yield-to-maturity plus current yield, Macaulay and modified duration and convexity from coupon, face, maturity and coupon frequency.
Add/subtract business days to a date, or count working days between two dates. Weekend- and custom-holiday-aware (0=Mon..6=Sun).
Return a month as a grid of week rows (weeks start Monday or Sunday), plus the weekday of the 1st, the day count, and whether it is a leap year.
Convert a color across hex/rgb/hsl/hsv/cmyk and (optionally) compute the WCAG contrast ratio and AA/AAA pass against a second color.
Future value of a lump sum plus recurring contributions: principal, annual rate, compounding frequency, contribution and years; returns balance curve, total contributed, total interest.
Liquidation price for a long/short leveraged (perp) position from entry, leverage and maintenance-margin rate; returns liquidation price and distance to it.
Remove duplicate rows from CSV text by all columns or a subset of key columns; returns cleaned CSV plus a report of how many rows were removed.
Column-level statistics for a CSV: inferred type, count, null count, distinct count, min/max/mean for numeric columns, and sample values. One-call data audit.
Validate and lint JSON, YAML, CSV, or XML. Returns a valid flag, the line/column of the first error when invalid, and a normalized (re-serialized) copy when valid.
One-call date math: diff two datetimes, add/subtract an interval, epoch<->ISO conversion, and reformatting via strftime.
Orders multiple debts by snowball (smallest balance) or avalanche (highest APR), simulates month-by-month payoff, and returns months-to-debt-free, total interest and interest saved vs minimums.
Compute the keccak256 hash and 4-byte function selector of a signature string, and optionally ABI-decode raw hex calldata given an ordered list of static Solidity types.
Convert amounts between Ethereum denominations (wei, kwei, mwei, gwei, szabo, finney, ether) with exact integer/decimal math -- no float error.
Convert between wei, gwei and ether (or arbitrary-decimal ERC20 amounts) with big-integer precision; optional USD valuation from a caller-supplied price.
Liquidity, leverage, profitability and efficiency ratios (current, quick, debt-to-equity, ROE, ROA, gross/net margin, interest coverage) from supplied statement line items.
Compute md5, sha1, sha256, sha512, sha3-256 and crc32 digests of text (or hex bytes) in a single call. Returns hex for each plus byte length.
Convert a supplied HTML string to clean Markdown: strips scripts/style/nav, preserves headings, bold, italic, links, lists, code, and blockquotes. No fetch.
ISO 13616 mod-97 IBAN validation with per-country length rules, plus SWIFT/BIC structure validation and country/bank-code extraction.
Validate an IBAN checksum and decode its country and BBAN, validate a US ABA routing number, check SWIFT/BIC format, or Luhn-check a card and detect its network. Auto-detects the kind if not given.
Build a valid RFC 5545 VCALENDAR from a list of events (or a CSV of events). Supports all-day and timed events, RRULE recurrence, location, and display alarms.
Impermanent loss % and hold-vs-LP value for a 50/50 pool from the price ratio (new/old) of the volatile asset; nets optional fees earned to show true LP outcome.
CIDR math for IPv4/IPv6: network, broadcast, netmask, wildcard, prefix, usable host range and count, mask<->prefix, plus optional contains check and subnet split.
Classify an IPv4/IPv6 address: version, public/private/loopback/link-local flags, integer and hex forms, reverse-DNS pointer, and optional CIDR membership test.
Convert a date to its ISO 8601 week-date (year, week number, weekday), ordinal day-of-year, quarter, and days remaining in the year.