Narwhal API
A connected reference-rate workflow across current rates, conversion, daily history, REST, and hosted MCP.
FX APIs compared
A practical shortlist for developers choosing an exchange-rate API. This comparison separates reference and indicative rates from trading-market feeds, then checks conversion, history, streaming, REST, and MCP access.
Decision
Choose Narwhal when its published currency coverage fits and you want current rates, decimal-safe conversion, stored daily history, and hosted MCP in one contract. Choose a specialist market-data provider when you need intraday bars, streaming, trading workflows, or longer documented history.
Provider shortlist
This is a focused comparison of providers already reviewed for Narwhal. It is not a claim that every FX API has been evaluated, and it does not treat indicative rates as executable quotes.
Fixer
A dedicated exchange-rate API with broad documented currency coverage and plan-based update frequency.
Open Exchange Rates
A specialist JSON FX API with more than 200 currencies and long daily history.
ExchangeRate-API
Simple all-rates and pair-conversion endpoints, including a no-key daily option.
XE Currency Data API
Commercial FX workflows needing broad fiat, central-bank, crypto, or precious-metal coverage.
API Ninjas
A simple FX API alongside a very broad catalogue of unrelated APIs.
Alpha Vantage
FX alongside equities, commodities, technical indicators, and other market data.
Compare the options
Best fit is not feature parity. Check the evidence and limitation together.
| Provider | Best for | Evidence checked | Important limitation |
|---|---|---|---|
| Narwhal API | A connected reference-rate workflow across current rates, conversion, daily history, REST, and hosted MCP. | The live contract publishes current rates, decimal-safe conversion, and stored historical observations under one account and quota. | Coverage, freshness, and genuine historical gaps must be checked; the product does not promise executable bank or trading quotes. |
| Fixer | A dedicated exchange-rate API with broad documented currency coverage and plan-based update frequency. | Its checked material documents 170 currencies, current and historical rates, conversion, fluctuation, and time-series workflows. | Rate semantics, base-currency access, update frequency, and endpoint availability depend on the selected plan. |
| Open Exchange Rates | A specialist JSON FX API with more than 200 currencies and long daily history. | Its documentation describes end-of-day history back to 1 January 1999 plus live, time-series, and conversion products. | Base currency, conversion, time-series, intraday, and bid/ask access vary materially by plan. |
| ExchangeRate-API | Simple all-rates and pair-conversion endpoints, including a no-key daily option. | Its official documentation covers Standard, Pair Conversion, enriched-data, and historical endpoints. | Open, free, and paid tiers differ in attribution, updates, history, limits, and redistribution terms. |
| XE Currency Data API | Commercial FX workflows needing broad fiat, central-bank, crypto, or precious-metal coverage. | XE documents 174 fiat currencies, alternate central-bank sources, conversion, and historical requests. | Packages, usage rights, caching, frequency, and request volume are commercially licensed and plan-specific. |
| API Ninjas | A simple FX API alongside a very broad catalogue of unrelated APIs. | Its checked documentation describes current and historical currency-pair endpoints with daily history extending to 1999. | The wider catalogue is not one financial-data model, and plan requirements must be checked per endpoint. |
| Alpha Vantage | FX alongside equities, commodities, technical indicators, and other market data. | Its documentation includes real-time exchange rates and intraday, daily, weekly, and monthly FX time series. | The product is much broader than Narwhal; entitlement and rate limits depend on the selected plan. |
Choose by requirement
Reference rates and conversion
Start with Narwhal when daily reference or indicative rates, deterministic decimal conversion, and MCP access cover the job.
Dedicated currency APIs
Compare Fixer, Open Exchange Rates, ExchangeRate-API, and XE when currency breadth, history, update frequency, or specialist commercial licensing drives the decision.
Intraday and streaming
Start with Alpha Vantage when the application is fundamentally a market-data workflow rather than a reference-rate lookup.
Long daily history
Compare Open Exchange Rates, API Ninjas, and ExchangeRate-API when the history window matters, then verify currencies, plans, licensing, and rate semantics.
Sources and review date
Each detailed provider page lists the first-party documentation used, its evidence boundaries, and its review date.
Reviewed: