Since I've never heard of HEY, here's the site: https://hey.com/

It's basically an email provider, but with different features and interesting ideas on how to manage emails. Don't understand why they can't provide an actual elevator pitch on the landing page, but have you read their long-winded message and then you still have to click on "How it works", scroll some more and read some paragraphs just to get an understanding of what it's all about...