Can I open-source Proton Mail Plus?
KINDA · partial or early alternativesKinda. Stalwart and Listmonk cover the core of Proton Mail Plus, but they're early or partial — expect gaps like sender reputation, deliverability, and suppression handling and provider-grade deliverability.
Proton Mail Plus: Email is infrastructure. Customers pay to avoid lost messages, broken auth, spam problems, and the reputational cost of a flaky inbox.
xsender reputation, deliverability, and suppression handling
xprovider-grade deliverability
xpush reliability across devices
xteam routing and shared inbox rules
xabuse response and security operations
These projects already replace it, free.
LListmonkHigh-performance single-binary newsletter and mailing list manager with campaigns, templates, and Postgres backendopen source↗SStalwartModern all-in-one mail server in Rust with JMAP, IMAP, and SMTP plus built-in spam filtering.open source↗What each one is, in full: Listmonk · Stalwart
no votes, no pay-to-list · just what's real
Proton Mail Plus pricing
| plan | monthly | annual (per mo) | what you get |
|---|---|---|---|
| proton free | $0/user | $0/user | 1 user; 1 email address; 500 MB Mail storage expandable to 1 GB; 150 messages/day; 25 MB attachments. |
| mail plus | $4.99/user | $3.99/user | 1 user; 10 email addresses; 15 GB shared Mail/Drive storage; 1 custom domain; 10 hide-my-email aliases; 25 MB attachments. |
| proton unlimited | $12.99/user | $9.99/user | 1 user; 15 email addresses; 500 GB shared storage; 3 custom domains; unlimited hide-my-email aliases. |
| proton duo | $19.99 | $14.99 | 2 users; 30 email addresses; 2 TB shared storage; 3 custom domains. |
| proton family | $29.99 | $23.99 | Up to 6 users; 90 email addresses; 3 TB shared storage; 3 custom domains. |
| proton visionary | $39.99 | $29.99 | Up to 6 users; 100 email addresses; 6 TB shared storage; 10 custom domains. |
free tier1 user; 1 email address; 500 MB Mail storage expandable to 1 GB; 150 messages/day; 25 MB attachment limit
billingmonthly + annual; auto-renews; 30-day prorated money-back guarantee; some accounts also offer 2-year cycles
hidden costsPaid 'unlimited' sending excludes bulk, promotional and programmatic mail, and each recipient counts separately. Downgrading while above the free storage cap restricts account functions until usage is reduced; custom domains must be bought separately.
price historyProton Unlimited (monthly): $11.99 → $12.99 (2023-07)
verified 2026-08-12 · source ↗
Can I open-source Proton Mail Plus?
Kinda. Listmonk covers the core of Proton Mail Plus, but there are real gaps: sender reputation, deliverability, and suppression handling, provider-grade deliverability. Read the honest list above before committing.
How much does Proton Mail Plus cost?
Proton Mail Plus costs about $4.99/month (Mail Plus, checked 2026-07-31), which is $59.88 per year.
What do I lose by replacing Proton Mail Plus?
Honestly: sender reputation, deliverability, and suppression handling; provider-grade deliverability; push reliability across devices; team routing and shared inbox rules; abuse response and security operations. If any of those are load-bearing for you, keep paying.
Is there an open-source alternative to Proton Mail Plus?
Yes: Listmonk (High-performance single-binary newsletter and mailing list manager with campaigns, templates, and Postgres backend) Stalwart (Modern all-in-one mail server in Rust with JMAP, IMAP, and SMTP plus built-in spam filtering.)