Rate-API
Hourly exchange rates for 160+ currencies in JSON, XML or CSV with free plan 2,500 requests/month
EU VAT number validation with company name and address lookup across all 27 member states.
TaxID API is a free Currency Exchange API that requires apiKey authentication, is served over HTTPS and has unconfirmed CORS support.
TaxID API reference. Validate EU VAT numbers with a single GET request. Authentication, endpoints, error codes, and code examples in Node.js, Python, PHP, and Ruby.
Details from taxid.dev.

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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
The TaxID API is provided by TaxID (taxid.dev). TaxID API reference. Validate EU VAT numbers with a single GET request. Authentication, endpoints, error codes, and code examples in Node.js, Python, PHP, and Ruby.
Yes. The TaxID 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.
Yes. The TaxID API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the TaxID API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The TaxID API is served over HTTPS, so it's safe to use in production.