Duo Data Utilities

33 small data utilities for software agents and developers: identifiers, dates and zones, text, encodings, geodesy, blockchain primitives, reference tables and number arithmetic. Each call is a plain HTTP GET (or a POST with a JSON body) that costs $0.05 (USDC on Base, paid over x402). No account, no API key, no cookies. Try it from a terminal: npx agentcash try https://api.duoleads.com

Identifiers and check digits

• /v1/id/national VAT number format and checksum (no VIES lookup), tax ID and national ID validator: 23 countries
• /v1/id/gs1 EAN/UPC barcode validator: GTIN, EAN-13, UPC-A (GTIN-12), GTIN-8/14, GLN and SSCC check digits
• /v1/id/security ISIN validator plus CUSIP, SEDOL and FIGI check-digit validation; builds an ISIN from an NSIN
• /v1/id/iban IBAN validator: length, mod-97 check digits, bank/branch/account breakdown (89 countries)
• /v1/id/iban-build IBAN generator: build an IBAN from country and BBAN or bank/branch/account, computing check digits

Dates, times and zones

• /v1/time/zone Timezone converter: instant to local time in an IANA time zone and back, with UTC offset and DST state
• /v1/time/dst DST transitions: next daylight-saving time changes for an IANA time zone
• /v1/time/business-days Business days calculator: add or count working days with your weekend mask and holiday list
• /v1/time/rrule RRULE expander: RFC 5545 recurrence rule to concrete occurrence dates
• /v1/time/calendar Calendar converter: Gregorian to Hijri, Hebrew, Japanese era, Persian and more, plus Easter date

Text and Unicode

• /v1/text/slug Slug generator: Unicode-aware URL slug with transliteration
• /v1/text/transliterate Cyrillic transliteration to Latin (ISO 9:1995, BGN/PCGN Russian)
• /v1/text/unicode Unicode normalization (NFC/NFKC), script detection and homoglyph/confusable check
• /v1/text/similarity String similarity: Levenshtein, Jaro-Winkler distance and Soundex/Metaphone phonetic keys

Encoding, parsing and digests

• /v1/code/url URL parser: parse, canonicalize and extract the registrable domain (eTLD+1)
• /v1/code/idn Punycode converter: IDN domain to ASCII and back, with IDNA2008 label validation
• /v1/code/semver Semver parser: parse and compare versions, check range satisfaction
• /v1/code/hash SHA-256/HMAC hash generator: SHA-256, SHA-512, SHA-3, Keccak-256, BLAKE2 and HMAC digests
• /v1/code/jwt JWT decoder: header, claims and expiry state (no signature verification)

Geodesy and geometry

• /v1/geo/geohash Geohash encoder and decoder with neighbour cells
• /v1/geo/pluscode Plus code (Open Location Code) encoder and decoder
• /v1/geo/polygon Point in polygon check, plus bounding box, centroid and area for GeoJSON
• /v1/geo/distance Distance calculator: geodesic distance, bearing and destination point on WGS-84

Blockchain primitives (no RPC)

• /v1/chain/address Crypto address validator: detect the blockchain and verify the checksum (EVM, Bitcoin, Solana and more)
• /v1/chain/selector Solidity function selector: Keccak-256, 4-byte selector and event topic from a signature

Static reference tables

• /v1/ref/nuts NUTS region lookup: EU statistical region codes, names and hierarchy
• /v1/ref/airport Airport lookup by IATA or ICAO code: name, coordinates, elevation, time zone; nearest airports
• /v1/ref/currency Currency lookup: ISO 4217 codes, names, minor units and cash rounding
• /v1/ref/country Country lookup: ISO 3166 codes, currency, TLD, UN region and ISO 3166-2 subdivisions

Numbers and money arithmetic

• /v1/num/radix Base converter: integers between number bases 2 to 36 (hex, binary, octal)
• /v1/num/words Number to words in 12 languages, with ordinal and currency forms
• /v1/num/stats Statistics calculator: mean, median, standard deviation, quartiles and percentiles
• /v1/num/allocate Money split: allocate an amount into shares with no rounding loss