{
  "protocol": "verified-facts/0.2",
  "publisher": {
    "name": "Data Butler",
    "url": "https://databutler.dev/"
  },
  "conformance": "L3",
  "updated": "2026-10-12",
  "facts": {
    "count": 496,
    "get": "https://databutler.dev/f/{key}",
    "batch": "https://databutler.dev/f?keys={keys}",
    "resolve": "https://databutler.dev/f/resolve?q={q}",
    "index": "https://databutler.dev/f",
    "filtering": "server",
    "examples": [
      "uk/income-tax/personal-allowance",
      "us/social-security/wage-base",
      "de/income-tax/grundfreibetrag",
      "uk/bank-rate"
    ]
  },
  "namespaces": [
    {
      "name": "uk",
      "description": "UK tax/NI thresholds, Bank of England Bank Rate, UK car tax (VED) and MOT rules, UK exam dates and UK government service steps, fees and processing times",
      "count": 404,
      "cadence": "uk-rates: Every 6 April (new tax year) and after each Budget or Autumn Statement; minimum wage on 1 April; every source page re-fetched weekly. policy-rates: After each scheduled decision (eight a year per bank); re-verified within 45 days of verifiedDate; every source page re-fetched weekly. uk-vehicle-rules: Every 1 April (VED rates and the historic-vehicle exemption date move with the Finance Act) and after each Budget; MOT fees and rules when DVSA changes them; every source page re-fetched weekly. uk-exam-dates: Annual, calendar-driven: when JCQ and the boards publish the following summer's final timetables (early in the calendar year) and the results days; the weekly watcher hashes the JCQ and board timetable pages uk-gov-process: Re-verified against the gov.uk pages every 30 days and on fee-change days (Home Office fees usually move in April); every source page re-fetched weekly through the gov.uk content API.",
      "authorities": [
        "qualifications.pearson.com",
        "qualifications.wales",
        "webarchive.nationalarchives.gov.uk",
        "www.aqa.org.uk",
        "www.bankofengland.co.uk",
        "www.gov.uk",
        "www.jcq.org.uk",
        "www.ocr.org.uk",
        "www.sqa.org.uk",
        "www.wjec.co.uk"
      ]
    },
    {
      "name": "us",
      "description": "Federal Reserve federal funds target range and US federal tax thresholds",
      "count": 45,
      "cadence": "policy-rates: After each scheduled decision (eight a year per bank); re-verified within 45 days of verifiedDate; every source page re-fetched weekly. us-rates: Annual: after the IRS tax-year inflation adjustments (October), the retirement-plan limits (November) and the SSA Federal Register notice (October/November); every source page re-fetched weekly.",
      "authorities": [
        "www.federalregister.gov",
        "www.federalreserve.gov",
        "www.irs.gov"
      ]
    },
    {
      "name": "de",
      "description": "German tax and social-insurance thresholds",
      "count": 44,
      "cadence": "de-rates: Annual: after the Sozialversicherungsrechengrößen-Verordnung and the Zusatzbeitrag announcement (November), and any Steuergesetz changing § 32a EStG for the next Veranlagungszeitraum; every source page re-fetched weekly.",
      "authorities": [
        "www.bmas.de",
        "www.bundesanzeiger.de",
        "www.bundesgesundheitsministerium.de",
        "www.deutsche-rentenversicherung.de",
        "www.gesetze-im-internet.de",
        "www.minijob-zentrale.de",
        "www.recht.bund.de"
      ]
    },
    {
      "name": "eu",
      "description": "ECB key interest rates",
      "count": 3,
      "cadence": "policy-rates: After each scheduled decision (eight a year per bank); re-verified within 45 days of verifiedDate; every source page re-fetched weekly.",
      "authorities": [
        "www.ecb.europa.eu"
      ]
    }
  ],
  "hash": "sha256/jcs",
  "signature": "EdDSA/jws-detached",
  "keys": "https://databutler.dev/.well-known/jwks.json",
  "changes": "https://databutler.dev/.well-known/changes.json",
  "openapi": "https://databutler.dev/openapi.json",
  "mcp": {
    "url": "https://databutler.dev/api/mcp/facts",
    "tools": [
      "get_fact",
      "resolve_fact",
      "what_changed_since"
    ],
    "serverCard": "https://databutler.dev/api/mcp/facts/server-card"
  },
  "schema": "https://databutler.dev/schema/fact.v0.json",
  "specification": "https://databutler.dev/protocol/facts",
  "licence": "Free to reuse with attribution to databutler.dev; each figure belongs to its official source and stays under that source's terms (gov.uk: Open Government Licence v3.0).",
  "contact": "https://github.com/physics-star-cat/databutler/issues"
}