Thanks for this, it's great! I will be implementing this in the future for sure.
I have one remark about the payment window... It would be great if we don't have to manually go to the @username/transfers page...
For example if a user can fill in their own username once, then the payment page remembers this with a cookie...
Then follow up visits can retrieve this cookie and offer a method to open the transfer window page without having to type it..
Will implement it! Thank you
For donation you need to set amount=0 ;-)
Thanks for showing us this jump page!