Can I open-source Mailient?
KINDA · partial or early alternativesKinda. Stalwart and Listmonk cover the core of Mailient, but they're early or partial — expect gaps like A mobile app and real push notifications, which is where most email actually gets read and Managed OAuth with Google and Microsoft, including the review process and token refresh pain.
Because email is the one app that has to work at 7am on a phone with two bars of signal, and a self-hosted poller on a home server does not clear that bar. People pay to skip OAuth verification, token refresh, IMAP quirks and the slow realization that their triage cron died four days ago and they missed an invoice. The AI part is commodity; the boring reliability around it is what the subscription actually buys.
xA mobile app and real push notifications, which is where most email actually gets read
xManaged OAuth with Google and Microsoft, including the review process and token refresh pain
xSomeone else absorbing provider API changes, rate limits and broken threading
xPolish: keyboard shortcuts, fast search, snooze, undo send, offline behavior
xAny sending reputation work if the product handles outbound at scale
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
Can I open-source Mailient?
Kinda. Listmonk covers the core of Mailient, but there are real gaps: A mobile app and real push notifications, which is where most email actually gets read, Managed OAuth with Google and Microsoft, including the review process and token refresh pain. Read the honest list above before committing.
How much does Mailient cost?
Mailient costs about $29/month (Monthly, checked 2026-08-18), which is $348 per year.
What do I lose by replacing Mailient?
Honestly: A mobile app and real push notifications, which is where most email actually gets read; Managed OAuth with Google and Microsoft, including the review process and token refresh pain; Someone else absorbing provider API changes, rate limits and broken threading; Polish: keyboard shortcuts, fast search, snooze, undo send, offline behavior; Any sending reputation work if the product handles outbound at scale. If any of those are load-bearing for you, keep paying.
Is there an open-source alternative to Mailient?
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.)