Posteo is a secure, green, and ad-free email provider based in Berlin that prioritizes user privacy and sustainability while providing a comprehensive suite of communication tools.

The principal functionalities of this service include:

1. Comprehensive Communication Suite

• Integrated Tools: Beyond email, the service includes a calendar, address book, and notes application.

• Storage & Aliases: Accounts start with 4 GB of upgradeable storage and include two alias addresses.

• Cross-Platform Sync: It is fully compatible with all devices and apps via standard protocols like IMAP, POP3, CalDAV, and CardDAV.

2. Industry-Leading Security and Encryption

• One-Touch Encryption: Users can encrypt their entire crypto mail storage, address book, and calendar at the touch of a button.

• Advanced Protection: Supports modern security standards such as Two-Factor Authentication (TOTP/Passkeys), PGP in the webmail interface, TLS-sending guarantees, and DANE technology.

• Privacy Infrastructure: Features professional spam/virus protection and IP stripping, which replaces the user's IP address with Posteo's to hide their location.

3. Radical Privacy and Anonymity

• Anonymous Setup: Registration requires no personal details (no name or address), and the service supports anonymous payment methods that are not linked to the account.

• No Commercial Exploitation: The platform is strictly ad-free and does not perform any tracking, user profiling, or data trading.

• Independent Financing: It is 100% financed by users (at a cost of 1 Euro per month), ensuring independence from investors or ad partners.

4. Holistic Sustainability

• Green Energy: All servers and offices are powered by 100% real green energy from Green Planet Energy.

• Ethical Operations: The company maintains a "resolute" sustainability model, including an organic canteen, no business flights, and utilizing ethical banks like Umweltbank and GLS Bank.

5. Seamless Transition Tools

• Automated Migration: A self-developed service allows users to migrate existing mailboxes (including folder structures), calendars, and contacts from other providers with just a few clicks.