Fastmail

Fastmail’s Masked Email feature can give a signup its own address while keeping messages in the main account. The help guide describes creating masks through integrations, organizing incoming mail with rules and using the masked address by default when replying. It is a useful distinction from merely adding a visible plus suffix to the same address.

The hosting service also lists spy-pixel protection, calendars and contacts. Its privacy policy rules out selling personal information and ad personalization, while describing operational processing such as spam and fraud detection. That is a subscriber-funded hosting model with privacy controls, rather than a blanket claim that the provider cannot process mailbox content.

The current homepage also offers a choice of primary data residency in the EU or USA. Include that account choice in a migration plan alongside domain, client and integration permissions.