Since most of currency converters are paid APIs - why not just use google for this task :)

Install currency-converter

// Menu: Currency Converter using google
// Author: Jakub Olek
// Twitter: @JakubOlek
/** @type {import("@johnlindquist/kit")} */
const from = await arg("from", ["pln", "usd", "eur"]);
const to = await arg("to", ["usd", "pln", "eur"]);
const query = await arg("amount");
const value = await scrapeSelector(
`https://google.com/search?q=${encodeURIComponent(
query + " " + from + " " + to
)}`,
"span[data-value]"
);
div(query + " " + from + " = " + value + " " + to, "p-4");