Apps: K‑9 Mail

Last updated: September 29, 2025

Summary Mature open‑source email client with IMAP/POP support, multiple identities, and OpenPGP integration.

Maintainer

  • K‑9 Mail project within the Thunderbird team

Repository

History

  • Longstanding Android email client; project partnered with Thunderbird (2022) with a roadmap to become “Thunderbird for Android”.

Why use it

  • Full‑featured mail with robust IMAP; privacy‑respecting; flexible notifications; works well with OpenKeychain/PGP providers.

Safe use

  • Use app‑specific passwords; disable remote images; prefer STARTTLS/TLS; verify server certificates; consider per‑folder sync to limit data.

Limits

  • Exchange/ActiveSync is not supported; initial setup can be more technical than mainstream clients.

Links