Currency Amount Converter (ECB Reference Rates)

{
  "type": "object",
  "required": [
    "amount",
    "from",
    "to"
  ],
  "properties": {
    "to": {
      "type": "string",
      "pattern": "^[A-Z]{3}$",
      "description": "The target currency as a three-letter uppercase ISO 4217 code."
    },
    "from": {
      "type": "string",
      "pattern": "^[A-Z]{3}$",
      "description": "The source currency as a three-letter uppercase ISO 4217 code."
    },
    "amount": {
      "type": "number",
      "description": "The amount of money to convert, in the source currency."
    }
  },
  "additionalProperties": false
}

{
  "type": "object",
  "properties": {
    "to": {
      "type": "string",
      "description": "The target currency code, echoed back."
    },
    "date": {
      "type": "string",
      "description": "The publication date (YYYY-MM-DD) of the reference rate used; it can be earlier than the day of the call."
    },
    "from": {
      "type": "string",
      "description": "The source currency code, echoed back."
    },
    "rate": {
      "type": "number",
      "description": "Units of the target currency per one unit of the source currency."
    },
    "amount": {
      "type": "number",
      "description": "The amount converted, echoed back."
    },
    "converted_amount": {
      "type": "number",
      "description": "The amount expressed in the target currency, rounded to two decimals."
    }
  },
  "description": "The conversion."
}