worked great for a long time, until openrates.io was bought(?) by exchangeratesapi.io - fix is to change background.js api url to 'http://api.exchangeratesapi.io/v1/latest?access_key='

…and WITHOUT the "&base=USD" part - that did not work and threw 'restricted base' and seems unnecessary.

Not really developer's fault :) rest of plugin seems to work just great!

I built and installed it with "temporary" in about:debugging

Writing here since I don't know how to contact you, LiabilityMan :)

There probably should be a field in plugin settings to include your api key though...