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Comparison · Comms
Stalwart vs Delta Chat
A side-by-side editorial comparison of Stalwart and Delta Chat — release velocity, themes, recent moves, and the top alternatives to consider.
Stalwart vs Delta Chat: at a glance
What is Stalwart?
Stalwart grinds toward standards-complete mail: DKIM2, DMARCbis, and a long JMAP conformance tail.
Stalwart is a self-hosted all-in-one mail and collaboration server (JMAP, IMAP, SMTP/MTA, CalDAV) shipping fortnightly point releases in the 0.16.x line. The work is overwhelmingly protocol conformance and correctness: closing JMAP test-suite gaps, hardening the MTA, and fixing calendar, auth, and cluster edge cases. Recent releases pair one or two standards additions with a dense list of subsystem fixes.
What is Delta Chat?
The email-as-messenger keeps shedding classic-email cruft for the Chatmail model
Delta Chat's desktop client ships frequent versioned releases centered on two threads: moving decisively onto the Chatmail relay model (removing classic-email folder and server-deletion options, dropping OAuth) and steady UX work — keyboard accessibility, multi-select, group profiles, WebXDC mini-apps, and calling. Releases are a mix of substantive feature drops and thin core-bump maintenance tags.
Stalwart vs Delta Chat: editorial side-by-side
Stalwart
5.0COMMS
Stalwart grinds toward standards-complete mail: DKIM2, DMARCbis, and a long JMAP conformance tail.
◆ Current state
Stalwart is a self-hosted all-in-one mail and collaboration server (JMAP, IMAP, SMTP/MTA, CalDAV) shipping fortnightly point releases in the 0.16.x line. The work is overwhelmingly protocol conformance and correctness: closing JMAP test-suite gaps, hardening the MTA, and fixing calendar, auth, and cluster edge cases. Recent releases pair one or two standards additions with a dense list of subsystem fixes.
◆ Where it's heading
The direction is depth over breadth — becoming the reference implementation for modern mail standards rather than adding new product surfaces. Over this window it added next-generation email authentication (DKIM2 draft, full DMARCbis suite), Web Push (VAPID/RFC 9749), IDN, FreeBSD support, and OAuth public-client flows, while steadily retiring JMAP conformance bugs. Security and privilege-boundary fixes recur, signaling a maturing codebase being pushed toward production trust.
◆ Prediction
Expect the 0.16.x cadence to continue with more JMAP conformance closeouts and DKIM2/DMARCbis stabilization as those drafts firm up; a 0.17 or 1.0 line would be the signal that the standards backlog has cleared.
Delta Chat
5.0COMMS
The email-as-messenger keeps shedding classic-email cruft for the Chatmail model
◆ Current state
Delta Chat's desktop client ships frequent versioned releases centered on two threads: moving decisively onto the Chatmail relay model (removing classic-email folder and server-deletion options, dropping OAuth) and steady UX work — keyboard accessibility, multi-select, group profiles, WebXDC mini-apps, and calling. Releases are a mix of substantive feature drops and thin core-bump maintenance tags.
◆ Where it's heading
The clear direction is Chatmail-native simplification: strip the legacy email-configuration surface so the app behaves like a messenger, not a mail client, while the server handles retention and relay. Alongside it, a keyboard-first desktop experience is forming (command palette, accessibility passes, shortcuts).
◆ Prediction
Expect more classic-email options to be retired, the experimental command palette to mature toward default, and continued investment in calling and WebXDC mini-apps.
Alternatives to Stalwart and Delta Chat
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 Delta Chat.
Respond.io
WhatsApp-first inbox teaching its AI agents conversational patience — and losing the phone number as identity.
Telnyx
Telnyx keeps pulling every layer of the voice-agent stack onto its own infrastructure.
Front
Front is spending its AI budget on control — which facts, which sources, which answers.
Elastic Email
Elastic Email is courting AI app builders, though only one real integration shipped.
Zoho Mail
An enterprise email suite leaning into admin depth, security, and an agent-facing inbox
See all Stalwart alternatives → · See all Delta Chat alternatives →
Recent activity from Stalwart and Delta Chat
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 1d agoStalwartv0.16.15 — JMAP, MTA, and auth privilege fixes
- 2d agoDelta Chatv2.57.0 release preparation
- 3d agoDelta ChatOAuth removed; group member search and command palette added
- 8d agoStalwartv0.16.14 — VAPID Web Push plus push and calendar fixes
- 15d agoStalwartv0.16.13 — FreeBSD support and OAuth/JMAP fixes
- 22d agoStalwartv0.16.12 — DKIM2 and DMARCbis email-authentication support
- 1mo agoStalwartv0.16.11 — S/MIME encryption-at-rest and Redis Sentinel backend
- 1mo agoDelta ChatMulti-message selection and keyboard accessibility work
- 1mo agoStalwartv0.16.10 — IDN, OAuth public clients, and a JMAP conformance pass
- 1mo agoDelta Chatv2.52.0 core update
- 1mo agoDelta ChatClassic-email folder and deletion options removed for Chatmail
- 3mo agoDelta ChatmacOS crash hotfix (v2.49.1)
Frequently asked questions
What is the difference between Stalwart and Delta Chat?
They serve adjacent needs but don't currently overlap on shipped themes. Stalwart and Delta Chat are shipping at a similar cadence (velocity 5.0 vs 5.0, both within Sparkpulse's "active" band). See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is Stalwart better than Delta Chat?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Stalwart and Delta Chat are shipping at a similar cadence (velocity 5.0 vs 5.0, both within Sparkpulse's "active" band). 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 Delta Chat?
Top Delta Chat alternatives in Comms are ranked by recent ship velocity. Browse the "Delta Chat alternatives" section above for the current picks, or visit /alternatives/deltachat for the full list with editorial commentary on each.