[opensourcedex]

best-of ranking · updated nightly

Best Open Source Email & Communication Tools

Ranked by GitHub stars — actual adoption, not editorial taste. All 10 are free, open source and self-hostable; license and last activity on every entry.

  1. 1
    Ntfy ★ 34K

    Simple, fast, and secure push notifications for all

    Apache-2.0 Go pushed 2026-09-15 details →
  2. 2
    Inbox Zero ★ 12K

    AI email assistant that automates, organizes, and declutters

    NOASSERTION TypeScript pushed 2026-09-17 details →
  3. 3
    Plunk ★ 5.5K

    The open-source, affordable email platform

    AGPL-3.0 TypeScript pushed 2026-09-14 details →
  4. 4
    useSend ★ 4.7K

    Pay per email sent, not for contact storage

    AGPL-3.0 TypeScript pushed 2026-09-08 details →
  5. 5
    Freescout ★ 4.5K

    Open-source helpdesk for seamless customer support

    AGPL-3.0 PHP pushed 2026-09-16 details →
  6. 6
    Keila ★ 2.2K

    Open-source email marketing for the privacy-conscious

    AGPL-3.0 Elixir pushed 2026-09-16 details →
  7. 7
    Sendportal ★ 2.2K

    Self-hosted email marketing with unlimited everything

    MIT PHP pushed 2024-04-19 details →
  8. 8
    UnInbox ★ 1.8K

    Transform team email into efficient collaborative workflows

    NOASSERTION TypeScript pushed 2026-02-11 details →
  9. 9
    DoubleZero ★ 1.2K

    Self-hosted email infrastructure for developers

    AGPL-3.0 Elixir pushed 2024-10-22 details →
  10. 10
    Sessy ★ 929

    Own your SES email analytics, from send to inbox

    NOASSERTION Ruby pushed 2026-09-15 details →
method stars desc · snapshot from github api refresh nightly related Input & Dictation, Office Suites, Password & Secret Management, Design & Visualization, Time & Task Management, System Cleanup & Optimization

Related best-of lists

best Input & Dictation →best Office Suites →best Password & Secret Management →best Design & Visualization →best Time & Task Management →best System Cleanup & Optimization →

last updated nightly · ranking method: github stars, live-tracked

Looking for a replacement for one specific commercial product? Browse alternatives by tool →

Frequently asked questions

What is the best open source Email & Communication tool in 2026?

Ntfy leads the ranking with 34,282 GitHub stars, ahead of Inbox Zero. Rankings use live GitHub star counts, refreshed nightly.

How is this list of Email & Communication tools ranked?

By GitHub stars — a proxy for adoption and community size. Each entry also shows its licence, primary language and last commit date, so you can judge maintenance activity rather than trusting the ranking alone.

Are the best Email & Communication tools free?

Every project on this list is open source and free to self-host. Some also offer paid managed hosting, but the software itself carries no licence fee.