XE API
XE (xe.com) has 2 public methods: convert currency and get historical exchange rate. Each costs 1 credit per completed run (1¢ with pay as you go); failed runs are free.
Unofficial. Not affiliated with or endorsed by XE.
Methods
2Converts an amount between two currencies using XE's displayed mid-market rate. It also returns the rate time and an XE converter link. Rates are informational, not transfer quotes.
Returns converted amount, rate, inverse rate, rate time, currency names, XE link
Readxe.com/convert_currencyGets XE's daily mid-market exchange rate for a past UTC date and converts an amount with it.
Returns date, currency codes and names, rate, inverse rate, converted amount, table link
Readxe.com/get_historical_rate