FabTally Utility Belt

FREE. Convert a value between units in the same dimension: length, mass, temperature, volume, data, time, area, speed, angle, pressure, energy. Deterministic. Args: value (number), from (unit), to (unit). e.g. {value:100, from:'c', to:'f'} or {value:1, from:'GiB', to:'MB'}. Different-dimension conversions 400.

PAID $0.001. Parse a 5- or 6-field cron expression and return the next N run times plus a plain-English description. Args: expression, timezone (IANA, default UTC), count (default 5), from (ISO, optional). Without payment returns the x402 challenge; pass x_payment to settle.

PAID $0.001. Convert an amount between currencies at reference/mid-market rates from a keyless public central-bank feed (ECB), cached. Informational, not a dealable quote. Args: amount, from, to (ISO-4217, e.g. USD, EUR, JPY). Without payment returns the x402 challenge; pass x_payment to settle.

PAID $0.001. Calendar date math. op='add'/'subtract' an ISO-8601 duration (P1Y2M10DT2H30M) to a date; op='diff' two datetimes into chosen units; op='business-add' add business days (configurable weekend + holidays); op='business-diff' count business days between two dates. Without payment returns the x402 challenge; pass x_payment to settle.

PAID $0.001. Diff two texts: a unified patch, a structured op-list (add/remove/equal), and add/remove/hunk stats. Args: a, b, mode (lines|words|chars, default lines), context (default 3), label_a, label_b. Without payment returns the x402 challenge; pass x_payment to settle.

FREE. Encode or decode text. op is one of base64-encode|base64-decode|base64url-encode|base64url-decode|hex-encode|hex-decode|url-encode|url-decode|html-encode|html-decode. Args: op, text.

FREE. Compute a cryptographic digest: sha256, sha512, sha384, sha1, md5, sha3-256, keccak256, ripemd160. Optional HMAC via hmac_key. Output hex (default), base64, or base64url. keccak256 also returns a 0x-form (handy for Ethereum). Args: algorithm, text (+ input_encoding utf8|hex|base64, output_encoding, hmac_key).

FREE. Generate identifiers. kind is one of uuidv4|uuidv7|ulid|nanoid|hex|base64url|int. count up to 1000. nanoid takes `size`; hex/base64url take `bytes`. Uses a CSPRNG. Args: kind, count.

PAID $0.001. Validate a value against a JSON Schema (draft 2020-12) and explain every error in plain English (which property, what was wrong, allowed values). Args: schema (object), data (any). Without payment returns the x402 challenge; pass x_payment to settle.

FREE. Run a regular expression against input with catastrophic-backtracking protection (it runs in a killable worker with a hard timeout, so a pathological pattern returns a 400 instead of hanging). op is test|match|extract|replace. Args: pattern, input, flags (gimsuy), op, replacement (for replace).

PAID $0.001. Expand an iCal RRULE (RFC 5545) recurrence into its next N occurrences. Args: rrule (e.g. 'FREQ=WEEKLY;BYDAY=MO,WE;COUNT=10'), after (ISO, default now), count (default 5), timezone. Tip: include DTSTART for anchored series. Without payment returns the x402 challenge; pass x_payment.

FREE. Text transforms. op='slugify' -> URL slug; op is one of camel|pascal|snake|kebab|constant|dot|path|title|sentence|upper|lower for case conversion; op='template' fills {{placeholders}} from `data`. Args: op, text (for slugify/case), or template + data (for template).

PAID $0.001 (x402, USDC on Base). Convert an instant between IANA time zones with historically-correct DST. Returns converted datetime, UTC offsets, tz abbreviations, DST flags, and the offset difference. Args: datetime (ISO 8601 or epoch), from_zone, to_zone. Without payment returns the x402 challenge; pass x_payment to settle. Free teaser exists on the HTTP API at /v1/timezone/free.