Sites and apps similar to CurrencyFreaks include Exchange-RateAPI, which has a free version. Other options are Open Exchange Rates. Between them they cover self-hosting.
Exchange-RateAPI is a real-time currency exchange rate API for developers, providing live and historical rates for 160+ currencies sourced from Reuters/Refinitiv and interbank feeds, updated continuously.
United Kingdom
Free, hourly-updated exchange rates and currency data - a simple, accurate, easy-to-integrate JSON API with great documentation. Free for personal use, a bargain for everybody else.
