I've now revamped the UI, added more domains and created an extension that shows your inbox in your browser (it only asks for permission to read from TemporaryMail.com and not all sites like the other extensions), it's also free from ads (paying the service out of pocket and perhaps adding an upgrade feature later on).
What makes this site a bit more unique is that I wrote the email parser from scratch following the RFC (took me 2 months and tons of testing) so it should display all incoming emails exactly as they are displayed in your favorite email client.
The site itself: https://TemporaryMail.com
Firefox Extension: https://addons.mozilla.org/en-US/firefox/addon/temporary-ema...
Chrome Extension: https://chromewebstore.google.com/detail/temporarymailcom-a-...
Edge Extension: https://microsoftedge.microsoft.com/addons/detail/temporarym...
Opera Extension: https://addons.opera.com/en/extensions/details/temporarymail...
Please give me your worst and criticize it to oblivion as I want to improve it. Also thinking about adding an API for it so let me know your thoughts on that too.
PS
I launched this back at the end of December 2020 and posted here on HN and it didn't get much traction.