Hi,
My name is George, I am a webdeveloper for over 10 years living and working in the Netherlands and I am strongly confident I can do this project in less than a week.
I am familiar with how Chrome extensions work, I have done them before, a JSON list available on your charity website should be enough.
Can you please send me the address of your website, so I can see what affiliate links you have and what patterns the links have (to be able to switch the user to the affiliate version of the exact page they where looking at)? So I can start planning the inner workings of the extension already.
Looking forward to working with you!
Best regards,
George Grigore