Exchange rates, geolocation and VAT number validation.
VATComply.com API is a free Currency Exchange API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Hourly exchange rates for 160+ currencies in JSON, XML or CSV with free plan 2,500 requests/month
Iran free-market USD, EUR, CNY, gold and coin rates in toman, live and daily archive since 2010
Yes. The VATComply.com API is listed in the Currency Exchange category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The VATComply.com API requires no authentication, so you can start making requests without signing up.
Yes. The VATComply.com API supports CORS, so front-end JavaScript can call it directly.
Yes. The VATComply.com API is served over HTTPS, so it's safe to use in production.