Tuta uses walled garden closed source apps. Posteo does not support custom domains unless you do something like addy.io. Mailbox.org does encryption at rest but your client needs to support pgp to use it. They all have their drawbacks.
Personally I’ve started to move from proton to mailbox.org with addy.io for custom domains and aliases. Once it’s solid I’m moving addy.io to self hosted
Posteo does not support custom Domains, because it’s unsafe and inherently complicated to use with all the security settings of a modern email system turned on
Tuta uses walled garden closed source apps. Posteo does not support custom domains unless you do something like addy.io. Mailbox.org does encryption at rest but your client needs to support pgp to use it. They all have their drawbacks.
Personally I’ve started to move from proton to mailbox.org with addy.io for custom domains and aliases. Once it’s solid I’m moving addy.io to self hosted
Posteo does not support custom Domains, because it’s unsafe and inherently complicated to use with all the security settings of a modern email system turned on