name: Fixer Vocabulary
description: |
  Controlled vocabulary for the Fixer foreign exchange rate API. Terms unify the
  operational dimensions (resources, endpoints, parameters, plans) with the
  capability dimensions exposed downstream (rate lookup, conversion, time-series
  analysis, fluctuation reporting).
url: https://raw.githubusercontent.com/api-evangelist/fixer/main/vocabulary/fixer-vocabulary.yml
created: '2026-05-29'
modified: '2026-05-29'
specificationVersion: '0.1'
provider: fixer
domain: Currency Exchange

dimensions:
  resources:
    - id: symbol
      label: Currency Symbol
      definition: An ISO 4217 three-letter currency code Fixer recognizes (170+ codes).
    - id: rate
      label: Exchange Rate
      definition: A signed quote of one currency expressed in units of another, anchored to a base currency.
    - id: conversion
      label: Conversion
      definition: An on-demand calculation translating an amount of one currency into another at a chosen rate.
    - id: timeSeries
      label: Time Series
      definition: A sequence of daily end-of-day rates between two dates for a given base/symbols pair.
    - id: fluctuation
      label: Fluctuation
      definition: A summarized comparison of start rate, end rate, absolute change, and percentage change between two dates.

  endpoints:
    - id: getSymbols
      label: List Supported Currency Symbols
      method: GET
      path: /symbols
    - id: getLatest
      label: Get Latest Exchange Rates
      method: GET
      path: /latest
    - id: getHistorical
      label: Get Historical Exchange Rates
      method: GET
      path: /{date}
    - id: convertCurrency
      label: Convert Currency Amount
      method: GET
      path: /convert
    - id: getTimeSeries
      label: Get Time Series Exchange Rates
      method: GET
      path: /timeseries
    - id: getFluctuation
      label: Get Fluctuation Data
      method: GET
      path: /fluctuation

  parameters:
    - id: base
      label: Base Currency
      definition: ISO 4217 currency code anchoring the rate set. Defaults to EUR; switchable on Basic and above.
    - id: symbols
      label: Symbol Filter
      definition: Comma-separated list of target currency codes that scopes the response.
    - id: from
      label: Source Currency
      definition: ISO 4217 code identifying the currency being converted out of.
    - id: to
      label: Target Currency
      definition: ISO 4217 code identifying the currency being converted into.
    - id: amount
      label: Conversion Amount
      definition: Numeric amount of the source currency to convert.
    - id: date
      label: Historical Date
      definition: ISO-8601 calendar date specifying a historical record.
    - id: start_date
      label: Window Start Date
      definition: First date in a time-series or fluctuation window.
    - id: end_date
      label: Window End Date
      definition: Last date in a time-series or fluctuation window.

  capabilities:
    - id: realtime-fx
      label: Real-Time FX Lookup
      definition: Retrieve current rates anchored to a chosen base, optionally filtered by symbol.
    - id: historical-fx
      label: Historical FX Lookup
      definition: Retrieve end-of-day rates for any working day since 1999-01-04.
    - id: currency-conversion
      label: Currency Conversion
      definition: Convert an amount from one currency into another at a real-time or historical rate.
    - id: timeseries-analysis
      label: Time Series Analysis
      definition: Pull a window of daily rates for trend analysis or backtesting (up to 365 days).
    - id: fluctuation-reporting
      label: Fluctuation Reporting
      definition: Summarize rate movement between two dates for risk monitoring and treasury reporting.

  commercial:
    - id: plan
      label: Subscription Plan
      values: [Free, Basic, Professional, "Professional Plus", Enterprise]
    - id: refreshRate
      label: Rate Refresh Cadence
      values: [Hourly, "10-minute", "60-second"]
    - id: httpsGating
      label: HTTPS Encryption Gating
      definition: HTTPS is restricted to paid plans (Basic and above); Free is HTTP only.
    - id: sourceCurrencySwitching
      label: Source Currency Switching
      definition: Ability to set the `base` parameter to a non-EUR currency; gated to Basic and above.

  data-sources:
    - id: ecb
      label: European Central Bank
      url: https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/html/index.en.html
      definition: Primary reference rates published daily around 4PM CET on working days.
    - id: multi-source
      label: Multi-Source Aggregation
      definition: Fixer blends 15+ exchange rate data providers to deliver 170+ supported currencies.

tags:
  - Currency Exchange
  - Foreign Exchange
  - FX
  - Conversion
  - ECB
  - Historical Rates
  - Time Series
  - Fluctuation
  - APILayer