Duo Data Utilities

{
  "name": "Duo Data Utilities",
  "description": "31 independent pay-per-call data utilities (identifiers, time, text, encodings, geodesy, blockchain primitives, reference tables, number arithmetic). $0.05 per call, payable over x402 (USDC on Base, eip155:8453). No account, no API key. A2A: JSON-RPC at https://api.duoleads.com/a2a; send a DataPart {\"skill\": \"<skill id>\", \"params\": {...}}; skill execution is paid through the a2a-x402 extension. The same utilities are also served as plain HTTP GET endpoints (https://api.duoleads.com/openapi.json) and as MCP tools over Streamable HTTP at https://api.duoleads.com/mcp (tools/list free, tools/call paid).",
  "supportedInterfaces": [
    {
      "url": "https://api.duoleads.com/a2a",
      "protocolBinding": "JSONRPC",
      "protocolVersion": "1.0"
    },
    {
      "url": "https://api.duoleads.com/a2a",
      "protocolBinding": "JSONRPC",
      "protocolVersion": "0.3"
    }
  ],
  "provider": {
    "organization": "Duo Leads",
    "url": "https://api.duoleads.com"
  },
  "version": "1.0.0",
  "documentationUrl": "https://api.duoleads.com/docs",
  "capabilities": {
    "streaming": false,
    "pushNotifications": false,
    "extensions": [
      {
        "uri": "https://github.com/google-agentic-commerce/a2a-x402/blob/main/spec/v0.2",
        "description": "Payment required per skill invocation: $0.05 in USDC on Base (eip155:8453), x402 v2, Standalone Flow. Required for skill execution (A2A-Extensions header); a message without a skill is answered for free.",
        "required": true
      }
    ]
  },
  "defaultInputModes": [
    "application/json"
  ],
  "defaultOutputModes": [
    "application/json"
  ],
  "skills": [
    {
      "id": "id.national",
      "name": "National identity- and company-number validation, 23 countries",
      "description": "Validate a national identity, tax or company registration number against its country's official checksum rule. Covers 23 countries including NL BSN, ES NIF/NIE/CIF, IT codice fiscale, FR SIREN/SIRET, DE Steuer-ID, BE/PL/CZ national numbers, SE/NO/DK/FI personal numbers, BR CPF/CNPJ, AU ABN/TFN, UK NINo, IE PPS, US NPI/EIN. Structure and check digit only \u2014 no registry lookup, no personal data stored. Price: $0.05 per call. Also GET /v1/id/national.",
      "tags": [
        "deterministic",
        "no-api-key",
        "id",
        "identifiers",
        "validation",
        "checksum"
      ],
      "examples": [
        "{\"skill\":\"id.national\",\"params\":{\"country\":\"NL\",\"kind\":\"bsn\",\"value\":\"111222333\"}}",
        "https://api.duoleads.com/v1/id/national?country=NL&kind=bsn&value=111222333"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "id.gs1",
      "name": "GS1 identifier validation: GTIN-8/12/13/14, GLN, SSCC",
      "description": "Validate and convert GS1 identifiers: GTIN-8, GTIN-12 (UPC-A), GTIN-13 (EAN-13), GTIN-14, GLN and SSCC. Returns the check-digit verdict, the computed correct check digit, the GS1 company-prefix boundary where it is derivable, and conversion to GTIN-14. Also computes a missing check digit from a partial code. Structure only, no product database. Price: $0.05 per call. Also GET /v1/id/gs1.",
      "tags": [
        "deterministic",
        "no-api-key",
        "id",
        "identifiers",
        "validation",
        "barcodes"
      ],
      "examples": [
        "{\"skill\":\"id.gs1\",\"params\":{\"value\":\"5901234123457\"}}",
        "https://api.duoleads.com/v1/id/gs1?value=5901234123457"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "id.security",
      "name": "ISIN, CUSIP, SEDOL and FIGI check-digit validation",
      "description": "Validate the check digit of a financial security identifier: ISIN (ISO 6166), CUSIP, SEDOL and FIGI. Returns the verdict, the computed correct check character, and for an ISIN the issuing country prefix and the embedded NSIN. Also builds an ISIN from a country code plus a 9-character NSIN. Format and checksum only, no security master lookup. Price: $0.05 per call. Also GET /v1/id/security.",
      "tags": [
        "deterministic",
        "no-api-key",
        "id",
        "identifiers",
        "validation",
        "finance"
      ],
      "examples": [
        "{\"skill\":\"id.security\",\"params\":{\"value\":\"US0378331005\"}}",
        "https://api.duoleads.com/v1/id/security?value=US0378331005"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "time.zone",
      "name": "Instant to wall-clock time in an IANA zone, with offset and DST state",
      "description": "Convert an instant to wall-clock time in a named IANA time zone, or a wall-clock time in a zone back to an instant. Returns the local date and time, the UTC offset in \u00b1HH:MM and seconds, the zone abbreviation, whether DST is in effect, the ISO week date, and the day of year. Handles the ambiguous and skipped local times at DST boundaries explicitly rather than guessing. Price: $0.05 per call. Also GET /v1/time/zone.",
      "tags": [
        "no-api-key",
        "time",
        "timezones"
      ],
      "examples": [
        "{\"skill\":\"time.zone\",\"params\":{\"zone\":\"Europe/Amsterdam\",\"instant\":\"2026-10-25T00:30:00Z\"}}",
        "https://api.duoleads.com/v1/time/zone?zone=Europe%2FAmsterdam&instant=2026-10-25T00%3A30%3A00Z"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "time.dst",
      "name": "Next daylight-saving transitions for an IANA time zone",
      "description": "List the daylight-saving transitions for an IANA time zone over a date range: the exact instant of each shift, the offset before and after, and whether local clocks jump forward or back. Returns the current offset and DST state, and the next transition from a given instant. Zones without DST return an empty transition list rather than an error. Price: $0.05 per call. Also GET /v1/time/dst.",
      "tags": [
        "no-api-key",
        "time",
        "timezones",
        "dst"
      ],
      "examples": [
        "{\"skill\":\"time.dst\",\"params\":{\"zone\":\"Europe/Amsterdam\",\"from\":\"2026-01-01\",\"years\":\"1\"}}",
        "https://api.duoleads.com/v1/time/dst?zone=Europe%2FAmsterdam&from=2026-01-01&years=1"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "time.business-days",
      "name": "Business-day arithmetic with a caller-supplied weekend mask and holiday list",
      "description": "Business-day arithmetic with a caller-supplied calendar: add or subtract N working days from a date, or count the working days between two dates. The weekend is specified as a weekday mask so Friday-Saturday and Sunday-only weeks work, and holidays are passed in as an explicit date list, so the answer never depends on a holiday table that can go stale. Returns the result date, the day count, and the first 1,000 skipped dates with the reason each was skipped. Price: $0.05 per call. Also GET /v1/time/business-days.",
      "tags": [
        "deterministic",
        "no-api-key",
        "time",
        "calendar",
        "business-days"
      ],
      "examples": [
        "{\"skill\":\"time.business-days\",\"params\":{\"from\":\"2026-12-24\",\"days\":\"5\",\"holidays\":\"2026-12-25,2026-12-26,2027-01-01\"}}",
        "https://api.duoleads.com/v1/time/business-days?from=2026-12-24&days=5&holidays=2026-12-25%2C2026-12-26%2C2027-01-01"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "time.rrule",
      "name": "RFC 5545 RRULE expansion into concrete occurrence timestamps",
      "description": "Expand an RFC 5545 recurrence rule into concrete occurrence timestamps. Accepts an RRULE string with DTSTART, an IANA time zone, and optional EXDATE and RDATE lists, and returns up to 200 occurrences as both local wall-clock times and UTC instants. Supports FREQ, INTERVAL, COUNT, UNTIL, BYDAY, BYMONTHDAY, BYMONTH, BYSETPOS and WKST. Occurrences moved by a DST gap carry gap: true. Rules needing over 50,000 candidate evaluations are rejected. Price: $0.05 per call. Also GET /v1/time/rrule.",
      "tags": [
        "deterministic",
        "no-api-key",
        "time",
        "calendar",
        "recurrence"
      ],
      "examples": [
        "{\"skill\":\"time.rrule\",\"params\":{\"rrule\":\"FREQ=MONTHLY;BYDAY=-1FR;COUNT=3\",\"dtstart\":\"2026-01-01T09:00:00\",\"zone\":\"Europe/Amsterdam\"}}",
        "https://api.duoleads.com/v1/time/rrule?rrule=FREQ%3DMONTHLY%3BBYDAY%3D-1FR%3BCOUNT%3D3&dtstart=2026-01-01T09%3A00%3A00&zone=Europe%2FAmsterdam"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "time.calendar",
      "name": "Gregorian conversion to Hijri, Hebrew and Japanese-era dates, plus Easter",
      "description": "Convert a Gregorian date to other calendar systems and back: Islamic (both the tabular civil calendar and the Umm al-Qura variant), Hebrew, Japanese imperial era, Republic of China, Buddhist and Persian. Also computes Easter Sunday for a year in both the Gregorian and Julian reckonings. Uses the calendar support built into the runtime, with the algorithm named in every response. Price: $0.05 per call. Also GET /v1/time/calendar.",
      "tags": [
        "deterministic",
        "no-api-key",
        "time",
        "calendar"
      ],
      "examples": [
        "{\"skill\":\"time.calendar\",\"params\":{\"date\":\"2026-09-28\",\"to\":\"islamic,hebrew,japanese\"}}",
        "https://api.duoleads.com/v1/time/calendar?date=2026-09-28&to=islamic%2Chebrew%2Cjapanese"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "text.slug",
      "name": "Unicode-aware URL slug with transliteration",
      "description": "Turn arbitrary text into a URL-safe slug. Decomposes accents, transliterates German umlauts, Scandinavian and Turkish letters, and the ligatures that lose meaning under plain NFD, lowercases, collapses separators, and truncates on a word boundary. Options for separator character, maximum length and case preservation. Returns the slug plus what was removed. Price: $0.05 per call. Also GET /v1/text/slug.",
      "tags": [
        "deterministic",
        "no-api-key",
        "text",
        "unicode",
        "slug"
      ],
      "examples": [
        "{\"skill\":\"text.slug\",\"params\":{\"text\":\"Cr\u00e8me Br\u00fbl\u00e9e \u2014 \u00c6r\u00f8sk\u00f8bing, Stra\u00dfe 42\",\"lang\":\"de\"}}",
        "https://api.duoleads.com/v1/text/slug?text=Cr%C3%A8me+Br%C3%BBl%C3%A9e+%E2%80%94+%C3%86r%C3%B8sk%C3%B8bing%2C+Stra%C3%9Fe+42&lang=de"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "text.transliterate",
      "name": "Cyrillic-to-Latin transliteration (ISO 9, BGN/PCGN)",
      "description": "Transliterate Cyrillic text into Latin using a named standard: ISO 9:1995 (one-to-one, with diacritics) or the BGN/PCGN Russian system. Returns the transliteration, the detected source script, the standard actually applied, the fraction of non-ASCII characters that were mapped, and any characters passed through untouched. Other scripts are not supported yet and are rejected with UNSUPPORTED_VALUE. Price: $0.05 per call. Also GET /v1/text/transliterate.",
      "tags": [
        "deterministic",
        "no-api-key",
        "text",
        "unicode",
        "transliteration"
      ],
      "examples": [
        "{\"skill\":\"text.transliterate\",\"params\":{\"text\":\"\u0429\u0443\u043a\u0430\",\"standard\":\"iso-9\"}}",
        "https://api.duoleads.com/v1/text/transliterate?text=%D0%A9%D1%83%D0%BA%D0%B0&standard=iso-9"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "text.unicode",
      "name": "Unicode normalisation, script detection and confusable/homoglyph analysis",
      "description": "Analyse a string at the Unicode level: apply NFC, NFD, NFKC or NFKD normalisation, report which normalisation forms it is already in, list the scripts present, and flag confusable and homoglyph characters \u2014 Cyrillic \u0430 in a Latin word, zero-width joiners, bidirectional overrides, invisible characters. Returns per-character detail for anything suspicious, with code points, names and the ASCII character each one imitates. Price: $0.05 per call. Also GET /v1/text/unicode.",
      "tags": [
        "deterministic",
        "no-api-key",
        "text",
        "unicode",
        "security"
      ],
      "examples": [
        "{\"skill\":\"text.unicode\",\"params\":{\"text\":\"caf\u00e9\",\"form\":\"nfd\"}}",
        "https://api.duoleads.com/v1/text/unicode?text=caf%C3%A9&form=nfd"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "text.similarity",
      "name": "String distance and phonetic keys: Levenshtein, Jaro-Winkler, Soundex, Metaphone",
      "description": "Compare two strings and return every standard similarity measure in one call: Levenshtein and Damerau-Levenshtein edit distance, normalised similarity, Jaro and Jaro-Winkler, longest common subsequence, Dice coefficient on character bigrams, and the Soundex, Metaphone and NYSIIS phonetic keys of each string. Optional case folding, accent folding and whitespace normalisation before comparison. Price: $0.05 per call. Also GET /v1/text/similarity.",
      "tags": [
        "deterministic",
        "no-api-key",
        "text",
        "similarity",
        "phonetic"
      ],
      "examples": [
        "{\"skill\":\"text.similarity\",\"params\":{\"a\":\"kitten\",\"b\":\"sitting\"}}",
        "https://api.duoleads.com/v1/text/similarity?a=kitten&b=sitting"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "code.url",
      "name": "URL parse, canonicalise, and registrable-domain (eTLD+1) extraction",
      "description": "Parse and canonicalise a URL, and extract its registrable domain using the Public Suffix List \u2014 the part an agent needs to decide whether two URLs belong to the same owner. Returns scheme, host, port, path, decoded query parameters and fragment, the public suffix, the registrable domain (eTLD+1), the subdomain, whether the suffix is an ICANN or a private entry, plus a canonical form with default port, dot-segments and percent-encoding normalised. unicode_host uses WHATWG/UTS 46 (non-strict). Price: $0.05 per call. Also GET /v1/code/url.",
      "tags": [
        "deterministic",
        "no-api-key",
        "code",
        "url",
        "domains",
        "psl"
      ],
      "examples": [
        "{\"skill\":\"code.url\",\"params\":{\"url\":\"https://a.b.example.co.uk:443/x/../y?q=1&q=2#f\"}}",
        "https://api.duoleads.com/v1/code/url?url=https%3A%2F%2Fa.b.example.co.uk%3A443%2Fx%2F..%2Fy%3Fq%3D1%26q%3D2%23f"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "code.idn",
      "name": "IDNA2008 / punycode conversion and domain-label validation",
      "description": "Convert internationalised domain names between Unicode and ASCII punycode in either direction, label by label, and validate each label against IDNA2008: length, leading and trailing hyphens, the hyphen-hyphen rule at positions 3 and 4, disallowed code points and bidirectional rules. Returns both forms, the per-label breakdown and the first rule violated. Strict mode is IDNA2008 (UTS 46 non-transitional); it may reject names /v1/code/url displays. Price: $0.05 per call. Also GET /v1/code/idn.",
      "tags": [
        "deterministic",
        "no-api-key",
        "code",
        "domains",
        "idna",
        "punycode"
      ],
      "examples": [
        "{\"skill\":\"code.idn\",\"params\":{\"domain\":\"b\u00fccher.example\"}}",
        "https://api.duoleads.com/v1/code/idn?domain=b%C3%BCcher.example"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "code.semver",
      "name": "Semantic-version parse, compare, and range satisfaction",
      "description": "Parse a semantic version into major, minor, patch, prerelease and build parts; compare two versions by precedence including prerelease ordering; or test whether a version satisfies a range expression using caret, tilde, hyphen, x-ranges and comparator sets. Returns the parsed structure, the comparison result and the reason a range did not match. Price: $0.05 per call. Also GET /v1/code/semver.",
      "tags": [
        "deterministic",
        "no-api-key",
        "code",
        "versions",
        "semver"
      ],
      "examples": [
        "{\"skill\":\"code.semver\",\"params\":{\"version\":\"1.2.3-rc.1+build.5\"}}",
        "https://api.duoleads.com/v1/code/semver?version=1.2.3-rc.1%2Bbuild.5"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "code.hash",
      "name": "SHA-2, SHA-3, BLAKE2 and HMAC digests of supplied text or base64 bytes",
      "description": "Compute a cryptographic digest of supplied data: SHA-256, SHA-384, SHA-512, SHA-1, SHA3-256, SHA3-512, Keccak-256, BLAKE2b-256 and BLAKE2b-512, plus HMAC with any of them. Input is UTF-8 text, base64 or hex bytes; output is hex, base64, base64url or base32. Returns the digest, the byte length of the input, and the exact algorithm identifier used. Price: $0.05 per call. Also GET /v1/code/hash.",
      "tags": [
        "deterministic",
        "no-api-key",
        "code",
        "crypto",
        "hashing"
      ],
      "examples": [
        "{\"skill\":\"code.hash\",\"params\":{\"algo\":\"sha256\",\"data\":\"hello\"}}",
        "https://api.duoleads.com/v1/code/hash?algo=sha256&data=hello"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "code.jwt",
      "name": "JWT structural decode: header, claims, expiry state \u2014 no signature verification",
      "description": "Decode a JSON Web Token without verifying it: returns the header, the claims, the signature length and algorithm, and a computed view of the time claims \u2014 whether exp has passed, whether nbf is in the future, and the remaining lifetime in seconds against a supplied or current instant. Reports structural problems such as a missing part, invalid base64url or an alg of none. It does not and cannot verify the signature; do not use it to decide trust. Price: $0.05 per call. Also GET /v1/code/jwt.",
      "tags": [
        "no-api-key",
        "code",
        "jwt",
        "security"
      ],
      "examples": [
        "{\"skill\":\"code.jwt\",\"params\":{\"token\":\"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c\",\"at\":\"2026-09-28T00:00:00Z\"}}",
        "https://api.duoleads.com/v1/code/jwt?token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c&at=2026-09-28T00%3A00%3A00Z"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "geo.geohash",
      "name": "Geohash encode and decode with neighbour cells",
      "description": "Encode a WGS-84 latitude and longitude to a geohash at a chosen precision, or decode a geohash back to its bounding box, centre point and error bounds in metres. Encoding also returns the eight neighbouring cells, which is what a caller needs to do proximity search over a geohash-indexed store without a spatial database. Price: $0.05 per call. Also GET /v1/geo/geohash.",
      "tags": [
        "deterministic",
        "no-api-key",
        "geo",
        "geohash"
      ],
      "examples": [
        "{\"skill\":\"geo.geohash\",\"params\":{\"op\":\"encode\",\"lat\":\"52.3728\",\"lon\":\"4.8936\",\"precision\":\"9\"}}",
        "https://api.duoleads.com/v1/geo/geohash?op=encode&lat=52.3728&lon=4.8936&precision=9"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "geo.pluscode",
      "name": "Open Location Code (plus code) encode and decode",
      "description": "Encode coordinates as an Open Location Code (plus code) at a chosen length, or decode a full code back to its bounding box and centre. Also shortens a full code against a reference coordinate and recovers a shortened code given a reference, which is how plus codes are normally exchanged in text. Returns code length, precision in metres and validity. Price: $0.05 per call. Also GET /v1/geo/pluscode.",
      "tags": [
        "deterministic",
        "no-api-key",
        "geo",
        "pluscode"
      ],
      "examples": [
        "{\"skill\":\"geo.pluscode\",\"params\":{\"lat\":\"52.3728\",\"lon\":\"4.8936\"}}",
        "https://api.duoleads.com/v1/geo/pluscode?lat=52.3728&lon=4.8936"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "geo.polygon",
      "name": "Point-in-polygon, bounding box, centroid and area on supplied GeoJSON",
      "description": "Geometric predicates on a GeoJSON geometry supplied in the request: point-in-polygon with correct hole handling, bounding box, centroid, signed area in square metres, perimeter length, and ring winding order. Accepts Polygon and MultiPolygon, and a GeoJSON Feature wrapping either. Area and length are geodesic on the WGS-84 ellipsoid, correct at any latitude; containment is planar in lon/lat. Price: $0.05 per call. Also GET /v1/geo/polygon.",
      "tags": [
        "deterministic",
        "no-api-key",
        "geo",
        "geojson",
        "geometry"
      ],
      "examples": [
        "{\"skill\":\"geo.polygon\",\"params\":{\"geometry\":\"{\\\"type\\\":\\\"Polygon\\\",\\\"coordinates\\\":[[[4.85,52.35],[4.95,52.35],[4.95,52.40],[4.85,52.40],[4.85,52.35]]]}\",\"lat\":\"52.3728\",\"lon\":\"4.8936\"}}",
        "https://api.duoleads.com/v1/geo/polygon?geometry=%7B%22type%22%3A%22Polygon%22%2C%22coordinates%22%3A%5B%5B%5B4.85%2C52.35%5D%2C%5B4.95%2C52.35%5D%2C%5B4.95%2C52.40%5D%2C%5B4.85%2C52.40%5D%2C%5B4.85%2C52.35%5D%5D%5D%7D&lat=52.3728&lon=4.8936"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "geo.distance",
      "name": "Geodesic distance, initial bearing and destination point on WGS-84",
      "description": "Distance and direction between WGS-84 coordinates: geodesic distance by Vincenty with a haversine fallback, initial and final bearing, the midpoint, and the destination point reached from a start point on a given bearing and distance. Also computes the cumulative length of a supplied coordinate path. Results in metres, kilometres, nautical miles and miles. Price: $0.05 per call. Also GET /v1/geo/distance.",
      "tags": [
        "deterministic",
        "no-api-key",
        "geo",
        "geodesy",
        "distance"
      ],
      "examples": [
        "{\"skill\":\"geo.distance\",\"params\":{\"lat1\":\"52.3728\",\"lon1\":\"4.8936\",\"lat2\":\"40.7128\",\"lon2\":\"-74.0060\"}}",
        "https://api.duoleads.com/v1/geo/distance?lat1=52.3728&lon1=4.8936&lat2=40.7128&lon2=-74.0060"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "chain.address",
      "name": "Blockchain address format detection and checksum validation",
      "description": "Identify which blockchain an address belongs to and validate its encoding: EVM EIP-55 checksum, Bitcoin base58check and bech32/bech32m with witness version, Solana base58 and on-curve check, Cosmos bech32 with its HRP, Tron, XRP, Litecoin, Dogecoin, Cardano, Polkadot SS58 and Algorand. Returns the detected chains with a confidence note, the checksummed form for EVM addresses, and the exact reason an address failed. Price: $0.05 per call. Also GET /v1/chain/address.",
      "tags": [
        "deterministic",
        "no-api-key",
        "chain",
        "blockchain",
        "addresses",
        "validation"
      ],
      "examples": [
        "{\"skill\":\"chain.address\",\"params\":{\"address\":\"0xd8da6bf26964af9d7eed9e03e53415d37aa96045\"}}",
        "https://api.duoleads.com/v1/chain/address?address=0xd8da6bf26964af9d7eed9e03e53415d37aa96045"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "chain.selector",
      "name": "Keccak-256 hash, 4-byte function selector and 32-byte event topic from a Solidity signature",
      "description": "Compute the Keccak-256 hash of a Solidity function or event signature and derive the 4-byte function selector and the 32-byte event topic. Normalises the signature first \u2014 strips parameter names, expands uint to uint256 and the other aliases, flattens tuples \u2014 so a signature copied from source code produces the same selector as the canonical form. Also hashes arbitrary text or hex bytes with Keccak-256. Price: $0.05 per call. Also GET /v1/chain/selector.",
      "tags": [
        "deterministic",
        "no-api-key",
        "chain",
        "blockchain",
        "solidity",
        "keccak"
      ],
      "examples": [
        "{\"skill\":\"chain.selector\",\"params\":{\"signature\":\"transfer(address,uint256)\"}}",
        "https://api.duoleads.com/v1/chain/selector?signature=transfer%28address%2Cuint256%29"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "ref.nuts",
      "name": "NUTS statistical region code lookup for the EU",
      "description": "Look up a NUTS statistical region of the European Union: resolve a NUTS code to its name, country and level, walk up to its parents or down to its children, or search regions by name. Covers all four levels (country, major region, basic region, small region) for the 27 member states and 12 further reporting countries, from the NUTS 2024 classification. Returns the Latin-script and local-language names plus the urbanisation, coastal and mountain typologies. Price: $0.05 per call. Also GET /v1/ref/nuts.",
      "tags": [
        "deterministic",
        "no-api-key",
        "ref",
        "eu",
        "statistics",
        "regions"
      ],
      "examples": [
        "{\"skill\":\"ref.nuts\",\"params\":{\"code\":\"NL32B\",\"include\":\"parents,typology\"}}",
        "https://api.duoleads.com/v1/ref/nuts?code=NL32B&include=parents%2Ctypology"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "ref.airport",
      "name": "Airport lookup by IATA or ICAO code with coordinates and elevation",
      "description": "Look up an airport by IATA or ICAO code and get its name, city, country, ISO 3166-2 region code, WGS-84 coordinates and elevation, or find the nearest airports to a coordinate within a radius. Covers every airport worldwide that holds a three-letter IATA code and scheduled service. Returns the code type that matched and the distance in kilometres for proximity results. Time zones are not included. Price: $0.05 per call. Also GET /v1/ref/airport.",
      "tags": [
        "deterministic",
        "no-api-key",
        "ref",
        "travel",
        "airports"
      ],
      "examples": [
        "{\"skill\":\"ref.airport\",\"params\":{\"code\":\"AMS\"}}",
        "https://api.duoleads.com/v1/ref/airport?code=AMS"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "ref.currency",
      "name": "Currency record (ISO 4217 codes, CLDR minor units and cash rounding)",
      "description": "Look up a currency by ISO 4217 code: its alphabetic and numeric codes, English name, minor-unit exponent, the smallest cash denomination where it differs from the minor unit, and the territories that use it. Returns the correct rounding increment for cash amounts, which is what a caller needs to render or settle a price. This route returns currency facts only and never an exchange rate. Price: $0.05 per call. Also GET /v1/ref/currency.",
      "tags": [
        "deterministic",
        "no-api-key",
        "ref",
        "finance",
        "currency",
        "iso-4217"
      ],
      "examples": [
        "{\"skill\":\"ref.currency\",\"params\":{\"code\":\"EUR\",\"include\":\"territories\"}}",
        "https://api.duoleads.com/v1/ref/currency?code=EUR&include=territories"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "ref.country",
      "name": "ISO 3166-1 country record: codes, currency, TLD, UN M49 region",
      "description": "Look up a country or territory by ISO 3166-1 alpha-2, alpha-3 or numeric code, or by name, and get the other codes, the English name, the UN M49 region and sub-region, the currencies in use, and the country-code top-level domain. Names are matched case- and accent-insensitively. Country level only: ISO 3166-2 subdivisions are not included. Price: $0.05 per call. Also GET /v1/ref/country.",
      "tags": [
        "deterministic",
        "no-api-key",
        "ref",
        "countries",
        "iso-3166"
      ],
      "examples": [
        "{\"skill\":\"ref.country\",\"params\":{\"code\":\"NL\"}}",
        "https://api.duoleads.com/v1/ref/country?code=NL"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "num.radix",
      "name": "Integer conversion between arbitrary numeric bases 2\u201336",
      "description": "Convert an integer between any two numeric bases from 2 to 36, with arbitrary precision so values far beyond 2^53 are exact. Accepts an optional sign and common prefixes (0x, 0b, 0o), validates every digit against the source base, and returns the value in the target base, in decimal, and as its bit length and digit count. Price: $0.05 per call. Also GET /v1/num/radix.",
      "tags": [
        "deterministic",
        "no-api-key",
        "num",
        "numbers",
        "conversion"
      ],
      "examples": [
        "{\"skill\":\"num.radix\",\"params\":{\"value\":\"0xdeadbeef\",\"to\":\"10\"}}",
        "https://api.duoleads.com/v1/num/radix?value=0xdeadbeef&to=10"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "num.words",
      "name": "Number spelled out in words, 12 locales, with ordinal and currency forms",
      "description": "Spell a number out in words in English, Dutch, German, French, Spanish, Italian, Portuguese, Polish, Russian, Turkish, Swedish or Japanese, in cardinal, currency or year form, and ordinal form in English, Dutch, German and French. Currency form applies the correct grammatical agreement and the right minor-unit name and count for the supplied ISO 4217 code. Handles negatives and values up to 10^15. Price: $0.05 per call. Also GET /v1/num/words.",
      "tags": [
        "deterministic",
        "no-api-key",
        "num",
        "numbers",
        "localisation"
      ],
      "examples": [
        "{\"skill\":\"num.words\",\"params\":{\"value\":\"1234\",\"lang\":\"nl\"}}",
        "https://api.duoleads.com/v1/num/words?value=1234&lang=nl"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "num.stats",
      "name": "Descriptive statistics and percentiles for a supplied numeric array",
      "description": "Descriptive statistics for a supplied numeric array in one call: count, sum, mean, median, mode, variance and standard deviation with variance and standard deviation honouring ddof (default 1, the sample form; 0 gives the population form) and always-population *_population fields, min, max, range, the quartiles and interquartile range, skewness, kurtosis, and any requested percentiles. Percentiles use a named interpolation method so the result is reproducible rather than implementation-defined. Price: $0.05 per call. Also GET /v1/num/stats.",
      "tags": [
        "deterministic",
        "no-api-key",
        "num",
        "numbers",
        "statistics"
      ],
      "examples": [
        "{\"skill\":\"num.stats\",\"params\":{\"values\":\"1,2,3,4,5\"}}",
        "https://api.duoleads.com/v1/num/stats?values=1%2C2%2C3%2C4%2C5"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    },
    {
      "id": "num.allocate",
      "name": "Split a money amount into shares with no rounding loss",
      "description": "Split a money amount into shares without losing or inventing a cent. Divide evenly into N parts, or by a list of ratios, and the remainder is distributed one minor unit at a time by a named, deterministic rule \u2014 largest-remainder, first-wins or last-wins \u2014 so the parts always sum exactly to the original. Uses Unicode CLDR minor-unit digits, so zero- and three-decimal currencies work (CLDR differs from ISO 4217 for a few, e.g. IDR, HUF: 0). Price: $0.05 per call. Also GET /v1/num/allocate.",
      "tags": [
        "deterministic",
        "no-api-key",
        "num",
        "finance",
        "money",
        "allocation"
      ],
      "examples": [
        "{\"skill\":\"num.allocate\",\"params\":{\"amount\":\"100.00\",\"currency\":\"EUR\",\"parts\":\"3\"}}",
        "https://api.duoleads.com/v1/num/allocate?amount=100.00&currency=EUR&parts=3"
      ],
      "inputModes": [
        "application/json"
      ],
      "outputModes": [
        "application/json"
      ]
    }
  ]
}