wish: online rates update for major cryptocurrencies

If there is a reliable free api that won't disappear or become payant in 2 months this can be studied. If you know such, please share here.

I am using "Alpha Vantage" free API for a couple of years now. It is simple to use, just needs a free API key to be generated. If you don't want to use a common key, maybe the option can be given so the homebank user can input their own key in the settings because there is a limitation:API call frequency is 5 calls per minute and 500 calls per day

example:
https://www.alphavantage.co/query?function=CURRENCY_EXCHANGE_RATE&from_currency=SOL&to_currency=USD&apikey=YOU_OWN_KEY

result in JSON:
{
    "Realtime Currency Exchange Rate": {
        "1. From_Currency Code": "SOL",
        "2. From_Currency Name": "Solana",
        "3. To_Currency Code": "USD",
        "4. To_Currency Name": "United States Dollar",
        "5. Exchange Rate": "21.97000000",
        "6. Last Refreshed": "2023-04-23 13:40:07",
        "7. Time Zone": "UTC",
        "8. Bid Price": "21.97000000",
        "9. Ask Price": "21.98000000"
    }
}

A second option which I am using is API from CoinMarketCap with similar results. https://coinmarketcap.com/api/documentation/v1/

from 2018174

for XAU

Would it maybe possible to take advantage of the platform wwe.xe.com?
It seems to be great for all currency exchange.

to choose between https://blog.apilayer.com/7-best-free-currency-converter-apis-in-2023/
or other

Alpha Vantage do not enable to get multiple rate at once, so I will go for fixer.io, user will need a free apikey.
Also fixer.io has exact same request and response than frankfurter.app, the current api.

exchangerate.host seems to offers the same than fixer.io, without the need of an api key

I have made a few flexible change for 5.7 final.
Added 2 parameters to change the API, fixer.io compatible
and changed from frankfurter.app (30 currency, no crypto) to exchangerate.host (170 currency)
but still BTC support only

=> so I keep this wish opened