Unfortunately they’re not accepting new signups

Oh, I hadn't noticed. Your service looks nice, and if spamgourmet is not taking new signups it does make even more sense.

Is there by chance a Firefox add-on on your product roadmap? This looks interesting

Thanks! It’s already available as a Firefox and chrome add on:

https://addons.mozilla.org/en-GB/firefox/addon/idbloc/

https://chrome.google.com/webstore/detail/idbloc-secure-and-...