Looks like it's not officially offered by Mullvad, but by this individual. Which is cool, except it exposes your account ID, which could be problematic given the 5 devices per account rule.
Basically that person buys a lot of topups and re-sells them through that website.
It's not an official reseller though, but it works.
reply
Yeah I think it's weird the site even offers to enter your account number tbh.
But I can vouch for it, the coupons indeed work.
reply
I think it's only because the API is there to be used. That's all.
reply
Oh yes, I missed that. Cool!
reply