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Mailu vs Proton Bridge

A side-by-side editorial comparison of Mailu and Proton Bridge — release velocity, themes, recent moves, and the top alternatives to consider.

Mailu vs Proton Bridge: at a glance

FeatureMailuProton Bridge
SectorCommsComms
Velocity score5.02.5
Sparks · 30d00
Top themesmaintenance-branch, roundcube, cve-patching, self-hosted-mailemail, imap, privacy, maintenance
Last editorial update6d ago17h ago
WebsiteVisit →Visit →

What is Mailu?

Mailu ships one pinned release per issue, and most of them are Roundcube's.

The 2024.06 branch releases on demand: an issue or PR comes in, a pinned version goes out, and the changelog is one or two lines. Four of the six most recent releases are webmail-driven — three Roundcube bumps in this window alone, the latest to 1.6.18 clearing a TLS-configuration warning, an earlier one to 1.6.17 closing two CVEs. The remainder are Mailu's own code: an X-Forwarded-By header fix tied to a published advisory, sieve field escaping that repaired autoreplies and closed an injection path, and two admin-UI form flow corrections.

Read the full Mailu trajectory →

What is Proton Bridge?

Proton Bridge spends its first release in ten weeks on crashes, memory bounds and dead code

v3.26.0 is a maintenance cut. The user-visible items are a macOS 27 crash fix, bounded CPU and memory in the Gluon RFC parser, deletion of orphaned unencrypted vaults once keychain access returns, and a meta+W shortcut. The rest is internal: two unused subsystems removed from go-proton-api, two Go toolchain bumps, gomock swapped for uber-go/mock, and June and July vulnerability patches folded in.

Read the full Proton Bridge trajectory →

Mailu vs Proton Bridge: editorial side-by-side

M
Mailu
COMMS
5.0

Mailu ships one pinned release per issue, and most of them are Roundcube's.

◆ Current state

The 2024.06 branch releases on demand: an issue or PR comes in, a pinned version goes out, and the changelog is one or two lines. Four of the six most recent releases are webmail-driven — three Roundcube bumps in this window alone, the latest to 1.6.18 clearing a TLS-configuration warning, an earlier one to 1.6.17 closing two CVEs. The remainder are Mailu's own code: an X-Forwarded-By header fix tied to a published advisory, sieve field escaping that repaired autoreplies and closed an injection path, and two admin-UI form flow corrections.

◆ Where it's heading

This is a maintenance branch behaving exactly as a maintenance branch should, and the pinned-version model is the product: operators get upstream security work packaged and tagged without tracking Roundcube themselves. The security items divide cleanly — most arrive from bundled components, a minority from Mailu's own code, and the project patches both on the same cadence. Nothing in this window suggests new capability is being developed on this branch.

◆ Prediction

Expect the next release to follow the same trigger: a Roundcube advisory or a client compatibility report producing a single-line changelog and a new pinned tag. Any feature work would be happening on the main version, which this feed does not cover.

P2.5

Proton Bridge spends its first release in ten weeks on crashes, memory bounds and dead code

◆ Current state

v3.26.0 is a maintenance cut. The user-visible items are a macOS 27 crash fix, bounded CPU and memory in the Gluon RFC parser, deletion of orphaned unencrypted vaults once keychain access returns, and a meta+W shortcut. The rest is internal: two unused subsystems removed from go-proton-api, two Go toolchain bumps, gomock swapped for uber-go/mock, and June and July vulnerability patches folded in.

◆ Where it's heading

Releases arrive in long gaps — ten weeks since v3.25.0 — and each one bundles a quarter of dependency hygiene with a handful of IMAP correctness fixes. The recurring theme is RFC 3501 conformance and resource bounds in the mail parser rather than new capability, which is what a local IMAP shim for an encrypted mailbox is supposed to look like.

◆ Prediction

Given the pattern of shipping OS-compatibility fixes shortly after a macOS release, the next cut is likely another maintenance bundle timed to whatever the current macOS version breaks.

Alternatives to Mailu and Proton Bridge

Other Comms products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either Mailu or Proton Bridge.

See all Mailu alternatives → · See all Proton Bridge alternatives →

Recent activity from Mailu and Proton Bridge

Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.

  1. 1d agoProton BridgeBridge 3.26.0: macOS 27 crash fix and bounded RFC parser resources
  2. 6d agoMailuRoundcube 1.6.18 bump clears a TLS-config warning
  3. 24d agoMailuAutoconfig fix for modern K-9 Mail
  4. 25d agoMailuRoundcube 1.6.17 closes two CVEs
  5. 1mo agoMailuSets X-Forwarded-By in response to a GHSA advisory
  6. 1mo agoMailuAdmin UI keeps form values on failed submit
  7. 1mo agoMailuEscapes sieve fields, fixing autoreplies with special characters
  8. 2mo agoProton BridgeBridge 3.25.0: IMAP and sync fixes bundled with dependency updates
  9. 3mo agoProton BridgeBridge 3.24.2 patch with a single-line note
  10. 4mo agoProton BridgeBridge 3.24.1 patch with a single-line note
  11. 4mo agoProton BridgeBridge 3.24.0 Nescio feature cut
  12. 4mo agoProton BridgeBridge 3.23.1 patch on the Margit line

Frequently asked questions

What is the difference between Mailu and Proton Bridge?

They serve adjacent needs but don't currently overlap on shipped themes. Mailu is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.

Is Mailu better than Proton Bridge?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Mailu is currently shipping more aggressively (velocity 5.0 vs 2.5), with 0 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Comms products to evaluate alongside.

What are the best alternatives to Mailu?

Top Mailu alternatives in Comms are ranked by recent ship velocity. Browse the "Mailu alternatives" section above for the current picks, or visit /alternatives/mailu for the full list with editorial commentary on each.

What are the best alternatives to Proton Bridge?

Top Proton Bridge alternatives in Comms are ranked by recent ship velocity. Browse the "Proton Bridge alternatives" section above for the current picks, or visit /alternatives/proton-bridge for the full list with editorial commentary on each.