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Stalwart vs Subsplash

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

Stalwart vs Subsplash: at a glance

FeatureStalwartSubsplash
SectorCommsComms
Velocity score5.06.3
Sparks · 30d00
Top themesmail-server, jmap, imap, rfc-compliancechurch-management, workflow-automation, ai-assistants, giving-reconciliation
Last editorial update23h ago13d ago
WebsiteVisit →

What is Stalwart?

Stalwart is chasing mail RFCs and its own storage layer at the same time

Stalwart ships roughly weekly, and the releases divide cleanly between standards implementation and correctness work. v0.16.18 turns toward resource control — bounds on decompressed inbound DMARC and TLS report size, a cap on RocksDB block-cache memory, column families tuned per access pattern, and a queue scheduler that stops rescanning from the earliest pending event. The preceding releases added IMAP UIDONLY, UIDBATCHES and MESSAGELIMIT, plus JMAP email push and VAPID.

Read the full Stalwart trajectory →

What is Subsplash?

Subsplash is wiring automation and AI through the church admin stack it already owned

Workflows came out of beta in mid-July with per-step email automation, then immediately gained completion notifications for team leaders. Around it, the administrative surfaces are being rebuilt in sequence: Transfers and reconciliation now tracks who reconciled what and when, Groups gained member limits with a Full badge and finder filters, and event managers can register guests and waive payments directly from the dashboard. The AI line is filling in too — Trends AI added media and campaign data on top of giving, people, attendance and groups, following the natural-language People Assistant in May.

Read the full Subsplash trajectory →

Stalwart vs Subsplash: editorial side-by-side

S5.0

Stalwart is chasing mail RFCs and its own storage layer at the same time

◆ Current state

Stalwart ships roughly weekly, and the releases divide cleanly between standards implementation and correctness work. v0.16.18 turns toward resource control — bounds on decompressed inbound DMARC and TLS report size, a cap on RocksDB block-cache memory, column families tuned per access pattern, and a queue scheduler that stops rescanning from the earliest pending event. The preceding releases added IMAP UIDONLY, UIDBATCHES and MESSAGELIMIT, plus JMAP email push and VAPID.

◆ Where it's heading

Two threads run through every release. One is RFC coverage across IMAP, JMAP, CalDAV and WebDAV, implemented close to the specification including drafts. The other is a long tail of protocol-conformance fixes, many of them cases where JMAP and IMAP disagreed about the same state. The newest release adds a third: memory and scheduling limits, which is what a server codebase starts doing when deployments get large enough for defaults to hurt.

◆ Prediction

Expect continued RFC additions across the JMAP and IMAP surfaces, with more of the storage-tuning work that v0.16.18 started as RocksDB deployments scale.

S6.3

Subsplash is wiring automation and AI through the church admin stack it already owned

◆ Current state

Workflows came out of beta in mid-July with per-step email automation, then immediately gained completion notifications for team leaders. Around it, the administrative surfaces are being rebuilt in sequence: Transfers and reconciliation now tracks who reconciled what and when, Groups gained member limits with a Full badge and finder filters, and event managers can register guests and waive payments directly from the dashboard. The AI line is filling in too — Trends AI added media and campaign data on top of giving, people, attendance and groups, following the natural-language People Assistant in May.

◆ Where it's heading

Two threads run in parallel and are starting to meet. One is turning manual church-admin chores into configured automation — workflows that send their own emails, notify on completion, and enforce group capacity without a staff member watching. The other is putting a natural-language layer over an increasingly complete data set, which only becomes useful once giving, attendance, media and campaigns all live in the same place. Recent releases have been closing the gaps in that data set.

◆ Prediction

The obvious convergence is Workflows becoming triggerable from the data — a Trends AI segment or People Assistant query that drops matching people onto a workflow board automatically. Reconciliation gaining an export or accounting-package integration is the other near-term candidate given how much structure was just added to Transfers.

Alternatives to Stalwart and Subsplash

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 Stalwart or Subsplash.

See all Stalwart alternatives → · See all Subsplash alternatives →

Recent activity from Stalwart and Subsplash

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

  1. 1d agoStalwartResource limits arrive for inbound reports and RocksDB caches
  2. 8d agoStalwartIMAP gains UIDONLY, UIDBATCHES and message-limit extensions
  3. 13d agoSubsplashTransfers & Reconciliation
  4. 16d agoStalwartJMAP delivery push arrives; strict relays stop rejecting calendar mail
  5. 20d agoSubsplashBe notified by email when a Workflow Card is complete
  6. 23d agoStalwartFix-only release: JMAP semantics and a credential escalation
  7. 29d agoStalwartVAPID lands for JMAP Web Push
  8. 1mo agoSubsplashIntroducing Group Member Limits + Group Finder Improvements
  9. 1mo agoSubsplashEmail Automations for Workflows
  10. 1mo agoStalwartFreeBSD support, plus OAuth scopes for IMAP, SMTP and Sieve
  11. 1mo agoSubsplashRegister Guests & Waive Payments from Dashboard
  12. 1mo agoSubsplashMedia and Campaign Data in Trends AI

Frequently asked questions

What is the difference between Stalwart and Subsplash?

They serve adjacent needs but don't currently overlap on shipped themes. Subsplash is currently shipping more aggressively (velocity 6.3 vs 5.0), 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 Stalwart better than Subsplash?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Subsplash is currently shipping more aggressively (velocity 6.3 vs 5.0), 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 Stalwart?

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

What are the best alternatives to Subsplash?

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