ECB Key Interest Rates: Deposit Facility, Main Refinancing, Marginal Lending

{
  "type": "object",
  "required": [
    "rate"
  ],
  "properties": {
    "rate": {
      "enum": [
        "DFR",
        "MRR_FR",
        "MRR_MBR",
        "MLFR"
      ],
      "type": "string",
      "description": "Which key rate: DFR the deposit facility rate (the ECB's policy rate in practice; negative from 2014-06-11 to 2022-07-26); MRR_FR the main refinancing operations rate, fixed-rate tenders (no observations from 2000-06-28 to 2008-10-14); MRR_MBR the main refinancing minimum bid rate, variable-rate tenders (only 2000-06-28 to 2008-10-14); MLFR the marginal lending facility rate. Percent per annum: 2.5 means 2.5%."
    },
    "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, and a date in the future returns the latest available. Omit for the latest observations. For MRR_FR a date from 2000-06-28 to 2008-10-14 returns its older 2000-06-27 observation; use MRR_MBR for that period."
    },
    "basis": {
      "enum": [
        "D",
        "B"
      ],
      "type": "string",
      "default": "D",
      "description": "D (default): the rate in force, one observation for every calendar day including weekends. B: only the dates the rate changed, one observation per change; its newest observation is the date of the LAST CHANGE, not today. Use B to list a rate's history cheaply, D for the rate on a day."
    },
    "last_n": {
      "type": "integer",
      "default": 1,
      "maximum": 366,
      "minimum": 1,
      "description": "How many observations to return, counting back from the latest (or from as_of). 1 (default) is the single latest observation; with basis D 366 is a year of daily levels, with basis B 100 is more than every change since 1999."
    }
  },
  "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 0:0:0:0:0:0:0. Its observations map a time-axis position to [value, OBS_STATUS, OBS_CONF, OBS_PRE_BREAK, OBS_COM]: value is the rate in percent (a number, possibly 0 or negative; null only on the end-of-series marker of the MRR_MBR change dates); OBS_STATUS is a position into THIS response's structure.attributes.observation, which lists only the codes present (A normal value, M missing value), so never read 0 as normal without checking.",
            "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 PCPA percent per annum, 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, REF_AREA, CURRENCY, PROVIDER_FM, INSTRUMENT_FM, PROVIDER_FM_ID, DATA_TYPE_FM); each key in a series' observations is a position into structure.dimensions.observation[0].values, whose `id` is the date (YYYY-MM-DD).",
  "additionalProperties": true
}