ECB Euro Foreign Exchange Reference Rates, Daily, Monthly and Annual

{
  "type": "object",
  "required": [
    "currency"
  ],
  "properties": {
    "as_of": {
      "type": "string",
      "pattern": "^(?:(?:200[1-9]|20[1-9][0-9])-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12][0-9]|3[01])|(?:0[469]|11)-(?:0[1-9]|[12][0-9]|30)|02-(?:0[1-9]|1[0-9]|2[0-8]))|20(?:0[48]|[2468][048]|[13579][26])-02-29)$",
      "description": "A calendar date, YYYY-MM-DD from 2001-01-01. The observations returned end on or before this date: a weekend or holiday returns the previous trading day, dated in the response, and a date in the future returns the latest available. For M and A only periods that have ended by this date are returned. Omit for the latest observations."
    },
    "last_n": {
      "type": "integer",
      "default": 1,
      "maximum": 260,
      "minimum": 1,
      "description": "How many observations to return, counting back from the latest (or from as_of). 1 (default) is the single latest rate; 260 is about a year of daily rates, 12 a year of monthly averages. The count includes holiday rows with a null value before May 2012."
    },
    "currency": {
      "enum": [
        "USD",
        "GBP",
        "JPY",
        "CHF",
        "CNY",
        "AUD",
        "CAD",
        "NZD",
        "SEK",
        "NOK",
        "DKK",
        "PLN",
        "CZK",
        "HUF",
        "RON",
        "TRY",
        "ISK",
        "ILS",
        "ZAR",
        "BRL",
        "MXN",
        "INR",
        "IDR",
        "KRW",
        "MYR",
        "PHP",
        "SGD",
        "THB",
        "HKD",
        "BGN",
        "HRK",
        "RUB",
        "ARS",
        "DZD",
        "MAD",
        "TWD"
      ],
      "type": "string",
      "description": "The ISO 4217 code of the currency to quote against the euro. The rate is units of this currency per ONE euro (USD 1.1225 means 1 EUR = 1.1225 USD; divide to convert dollars to euro). Series that have ended: BGN to 2025-12-31, HRK to 2022-12-30, RUB to 2022-03-01, ARS, DZD, MAD and TWD to 2020-10-30; asking for their latest rate returns that last old observation, dated in the response."
    },
    "frequency": {
      "enum": [
        "D",
        "M",
        "A"
      ],
      "type": "string",
      "default": "D",
      "description": "D daily reference rate (default; one value per trading day, rounded by the ECB to 2 to 5 decimals depending on the currency); M the average of the daily rates over a calendar month; A the average over a calendar year. M and A count only complete months and years and are not rounded."
    }
  },
  "additionalProperties": false
}

{
  "type": "object",
  "required": [
    "header",
    "dataSets",
    "structure"
  ],
  "properties": {
    "header": {
      "type": "object",
      "description": "Response envelope: id, prepared (timestamp), and sender.id, which is ECB.",
      "additionalProperties": true
    },
    "dataSets": {
      "type": "array",
      "items": {
        "type": "object",
        "required": [
          "series"
        ],
        "properties": {
          "series": {
            "type": "object",
            "description": "The series, keyed by position string such as 0:0:0:0:0. Its observations map a time-axis position to [value, OBS_STATUS, OBS_CONF, OBS_PRE_BREAK, OBS_COM]: value is a number, or null on a holiday row before May 2012; OBS_STATUS is a position into THIS response's structure.attributes.observation, which lists only the codes present (A normal value, H missing value; holiday or weekend), so never read 0 as normal without checking; OBS_COM, when not null, is a position of the comment (Indicative rate).",
            "additionalProperties": true
          }
        },
        "additionalProperties": true
      },
      "description": "One data set. Its `series` object holds the single requested series: `attributes` (positions into structure.attributes.series, among them TITLE, UNIT and DECIMALS) and `observations`."
    },
    "structure": {
      "type": "object",
      "description": "The legend that decodes dataSets: dimensions.series (code lists), dimensions.observation[0].values (the time axis, one entry per observation returned, each with its date `id`), attributes.series (TITLE, UNIT, DECIMALS ...) and attributes.observation (the status legend).",
      "additionalProperties": true
    }
  },
  "description": "The ECB's SDMX-JSON 1.0 response, unchanged. Each key in dataSets[0].series is a colon-joined list of positions into structure.dimensions.series (FREQ, CURRENCY, CURRENCY_DENOM, EXR_TYPE, EXR_SUFFIX); each key in a series' observations is a position into structure.dimensions.observation[0].values, whose `id` is the date (YYYY-MM-DD, YYYY-MM or YYYY).",
  "additionalProperties": true
}