Posteo is truly ad-free, does not even advertise the services it offers. It costs 1€ per month, which I found is one of the cheapest not-for-free services around.The company publishes statistics about the requests from authorities and shares several important values. For example they run their servers with green energy and donate money to charities.Posteo features Mailvelope integration for end-to-end encryption and a calendar. Emails, contacts and calendars can be encrypted, the user can choose the encryption key, and the Search tool also works on encrypted data.My only critics: the look 'n feel of the web interface is old-school and the learning curve is steep. It took me quite some time to feel comfortable with it, but I could eventually find pretty much everything I was looking for.
Open source, supports encryption and calendaring. One of the better privacy-oriented email services. A strong competitor against Protonmail, Mailbox.org and Tutanota.
Alternative to GAFAM using Green energy!
Use it personally, good price, environmentally friendly, and reliable service. Contact features can be a little limited (ie not an easy "favorite" method), and there is not an easy way to track an external website .ics calendar, but otherwise really gets the job done.
[Edited by jtflynnz, March 23]
Also forgot to mention, you can have them encrypt your mailbox with a password of your choosing; they do not store this password, so there is no way to recover this. If you choose to go with this option, make sure to keep a record of it safe.
Additionally, they allow for 2-factor authentication, as well as card- and cal-dav syncing of contacts and calendar to clients (ie mobile).
I've used Posteo for over a month now, and so far I've had no problems whatsoever. The emails arrive as they should and the web GUI is okay. There is a setting to enable encryption, preventing even the company from reading your emails. The service is located in Germany, which means they can't be legally forced to backdoor your email account to send everything you do to the police.
Thunderbird + TorBirdy on my computer works very well. The service is really Tor friendly.K-9 on my Android also works very well, especially since K-9 has support for identities or aliases as Posteo calls them.
My only nitpick is that I think there should be more aliases. For a euro per month you can't really complain though. I also think the name "Posteo" sounds odd in non-English languages, but that's probably just me.
If you're looking for a Gmail/Outlook alternative, I'd say this one is the best I've tried so far!
Our users have written 5 comments and reviews about Posteo, and it has gotten 55 likes