openapi: 3.0.3
info:
  title: FXRates Convert Historical Rates API
  description: 'FXRatesAPI is a foreign exchange rates REST API serving real-time and historical currency exchange rates for 185+ fiat currencies plus major cryptocurrencies and precious metals. All endpoints return JSON over HTTPS from the base host https://api.fxratesapi.com. A limited tier is usable without an API key; a paid API key (passed as the api_key query parameter or an Authorization Bearer header) raises quotas, increases update frequency, and unlocks base-currency switching.


    Endpoint paths, methods, and parameters below are grounded in live probes of the API on 2026-07-12. Response schemas are modeled from the observed JSON payloads rather than a provider-published machine-readable schema, and only parameters confirmed during probing are asserted; additional optional parameters may exist.'
  version: '1.0'
  contact:
    name: FXRatesAPI
    url: https://fxratesapi.com
  termsOfService: https://fxratesapi.com/legal/terms-conditions
servers:
- url: https://api.fxratesapi.com
  description: FXRatesAPI production
security:
- {}
- apiKeyQuery: []
- bearerAuth: []
tags:
- name: Historical Rates
  description: Exchange rates for a specific past date.
paths:
  /historical:
    get:
      operationId: getHistoricalRates
      tags:
      - Historical Rates
      summary: Get historical exchange rates for a date
      description: Returns the exchange rates as they were on a specific past date.
      parameters:
      - name: date
        in: query
        required: true
        description: The date to retrieve rates for, in YYYY-MM-DD format.
        schema:
          type: string
          format: date
          example: '2026-01-01'
      - name: base
        in: query
        required: false
        description: Base currency code (ISO 4217). Defaults to USD.
        schema:
          type: string
          default: USD
      - name: currencies
        in: query
        required: false
        description: Comma-separated list of currency codes to return.
        schema:
          type: string
      - name: api_key
        in: query
        required: false
        schema:
          type: string
      responses:
        '200':
          description: Historical exchange rates for the requested date.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RatesResponse'
        '400':
          $ref: '#/components/responses/Error'
components:
  schemas:
    RatesResponse:
      type: object
      description: Modeled from observed /latest and /historical JSON payloads.
      properties:
        success:
          type: boolean
          example: true
        terms:
          type: string
          example: https://fxratesapi.com/legal/terms-conditions
        privacy:
          type: string
          example: https://fxratesapi.com/legal/privacy-policy
        timestamp:
          type: integer
          description: Unix timestamp of the rate snapshot.
          example: 1783883940
        date:
          type: string
          format: date-time
          example: '2026-07-12T19:19:00.000Z'
        base:
          type: string
          example: USD
        rates:
          type: object
          description: Map of currency code to exchange rate against the base.
          additionalProperties:
            type: number
          example:
            EUR: 0.8761481387
            GBP: 0.7461771444
    ErrorResponse:
      type: object
      description: Modeled from observed error payloads. FXRatesAPI returns success=false with either a nested error object ({message}) or a flat error string plus a description field, depending on the endpoint and failure mode.
      properties:
        success:
          type: boolean
          example: false
        error:
          oneOf:
          - type: string
            example: missing_from_currency
          - type: object
            properties:
              message:
                type: string
                example: Endpoint Not Found
        description:
          type: string
          example: The from currency is required for the convert endpoint.
  responses:
    Error:
      description: Error response.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
  securitySchemes:
    apiKeyQuery:
      type: apiKey
      in: query
      name: api_key
      description: API key passed as the api_key query parameter.
    bearerAuth:
      type: http
      scheme: bearer
      description: 'API key passed as an Authorization: Bearer <API_KEY> header.'