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K-9 Mail (Thunderbird for Android) project preview
CommunicationAlternative to Spark MailAlternative to Gmail AppAlternative to Outlook Mobile

K-9 Mail (Thunderbird for Android)

Open-source email client for Android with support for multiple accounts and OpenPGP.

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LicenseApache-2.0
GitHub stars9.5k
Last commit1 weeks ago
Tags6 topics
KotlinCommunicationMobile ClientAndroid EmailImap PushOpenpgp
Overview

Why consider K-9 Mail (Thunderbird for Android)?

K-9 Mail is a free and open-source email client for Android (transitioning into Thunderbird for Android). It features IMAP push email, multi-folder synchronization, message flagging, signatures, and OpenPGP/APG encryption.

Guided learning

Learn K-9 Mail (Thunderbird for Android) by building

Practical setup notes, real use cases, and copy-ready examples in one focused guide.

1 min read 2 sections
In this guide2 sections

Overview of K-9 Mail

K-9 Mail delivers privacy-respecting Android email without proprietary cloud tracking or notification relays.

Installation

Download K-9 Mail from F-Droid or Google Play Store.

K-9 Mail is licensed under the Apache License Version 2.0.

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K-9 Mail (Thunderbird for Android) FAQs

K-9 Mail (Thunderbird for Android) is listed as a Communication tool on TiloBox. Review the overview, features, and official documentation on this page to decide whether it solves your specific workflow.

Start with the project's GitHub repository and official website for supported installation and deployment instructions. Test the setup with representative data or a small project before rolling it out more widely.

K-9 Mail (Thunderbird for Android) is listed under the Apache-2.0 license. Read the complete license text and the project's notices before using, modifying, or distributing the software.

Production readiness depends on your requirements. Review maintenance activity, security practices, documentation, backup and upgrade procedures, and compatibility with your stack; then validate it in a non-production environment.

K-9 Mail (Thunderbird for Android) is listed as an alternative to Spark Mail. Compare the core workflow, deployment model, integrations, and licensing against your must-have requirements before switching.