Proton Mail Plus alternatives: 2 open-source picks
Proton Mail Plus costs $4.99/mo — $59.88 a year. These 2 alternatives replace it for $0, led by Stalwart and Mailcow. All 2 are open source. License, stars and last commit checked by hand on 2026-09-13. No trials, no crippled tiers.
Modern all-in-one mail server in Rust with JMAP, IMAP, and SMTP plus built-in spam filtering.
licenseAGPL-3.0
runsyour server
setupnot verified by us yet — check the repo README
facts verified 2026-08-29
Dockerized full mail server suite — SMTP, IMAP, webmail, antispam, DKIM — with a slick admin UI.
licenseGPL-3.0
runsyour server
setupnot verified by us yet — check the repo README
facts verified 2026-09-13
What each one is, in full: Stalwart · Mailcow
last updated 2026-09-13 · no votes, no pay-to-list · just what's real
how to choose a Proton Mail Plus alternative
Most proven
Stalwart, with 14,652 GitHub stars — the largest community of the 2, which usually means more answers when something breaks.
what you give up by leaving Proton Mail Plus
- sender reputation, deliverability, and suppression handling
- provider-grade deliverability
- push reliability across devices
- team routing and shared inbox rules
- abuse response and security operations
None of the picks above covers all of it. The full verdict says which gaps matter.
Proton Mail Plus alternatives at a glance
| tool | license | running it | platforms | stars | active |
|---|---|---|---|---|---|
| Stalwart | AGPL-3.0 | docker to self-host | self-hosted, web | 14,652 | 2026-09 |
| Mailcow | GPL-3.0 | docker to self-host | self-hosted, web | 13,422 | 2026-09 |
why people still pay for Proton Mail Plus
Proton Mail Plus: Email is infrastructure. Customers pay to avoid lost messages, broken auth, spam problems, and the reputational cost of a flaky inbox. If none of that applies to you, any pick above saves $59.88 a year.
questions about switching from Proton Mail Plus
Is there an open-source alternative to Proton Mail Plus?
Yes: Stalwart, Mailcow. Every tool on this page is open source: no trials, no crippled tiers.
Can open source really replace Proton Mail Plus?
Our verdict is YES. Stalwart (15k stars), Mailcow (13k stars) are mature open-source replacements for Proton Mail Plus — self-host with docker and stop paying $4.99/mo. The full verdict, and what you give up by switching, is at caniopensourceit.online/proton-mail-plus.
What is the most popular open-source Proton Mail Plus alternative?
By GitHub stars, Stalwart (14,652). Mailcow is next with 13,422.
