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Comparison · Comms
Mailu vs Respond.io
A side-by-side editorial comparison of Mailu and Respond.io — release velocity, themes, recent moves, and the top alternatives to consider.
Mailu vs Respond.io: at a glance
| Feature | Mailu | Respond.io |
|---|---|---|
| Sector | Comms | Comms, Support |
| Velocity score | 5.0 | 7.5 |
| Sparks · 30d | 0 | 0 |
| Top themes | maintenance-branch, roundcube, cve-patching, self-hosted-mail | customer-messaging, ai-agents, omnichannel, tiktok-business |
| Last editorial update | 1mo ago | 13d ago |
| Website | 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.
What is Respond.io?
Respond.io upgraded its AI Agents to GPT-5.6 and added TikTok Business Messaging for US accounts.
Respond.io is shipping across three tracks simultaneously: AI Agent improvements (GPT-5.6 model upgrade, pre-publish instruction review), channel expansion (TikTok Business Messaging for US, Microsoft 365/Outlook email), and workflow automation (missed call auto-follow-up, Google Calendar integration). The status persistence fix — keeping agents online as long as the tab is open — addresses a real reliability concern for teams that rely on online/offline presence for routing.
Mailu vs Respond.io: editorial side-by-side
Mailu
5.0COMMS
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.
Respond.io
7.5COMMSSUPPORT
Respond.io upgraded its AI Agents to GPT-5.6 and added TikTok Business Messaging for US accounts.
◆ Current state
Respond.io is shipping across three tracks simultaneously: AI Agent improvements (GPT-5.6 model upgrade, pre-publish instruction review), channel expansion (TikTok Business Messaging for US, Microsoft 365/Outlook email), and workflow automation (missed call auto-follow-up, Google Calendar integration). The status persistence fix — keeping agents online as long as the tab is open — addresses a real reliability concern for teams that rely on online/offline presence for routing.
◆ Where it's heading
The product is converging on a model where AI Agents handle routine conversations while human agents handle escalations, with channels increasingly auto-enrolled (missed calls become conversations, calendar events surface in the inbox). The channel expansion pace (TikTok, Microsoft 365, Google Calendar within weeks) suggests a deliberate push to cover every channel a business customer might use.
◆ Prediction
Voice channel integration — handling inbound calls with AI Agents rather than just converting missed calls into follow-ups — would complete the omnichannel picture respond.io is assembling.
Alternatives to Mailu and Respond.io
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 Respond.io.
Superhuman
Superhuman rebuilt its mobile apps and wired every inbox into AI assistants — the email client is becoming a suite.
Chatwoot
Chatwoot is building an AI-first support platform, with Captain gaining audience targeting and macro automation reaching the keyboard-native workflow.
Signal Desktop
Signal adds granular notification controls: badge content, muted threads, restore defaults
Zoho Cliq
Zoho Cliq 7.0 bets on AI conversation summaries and Neat hardware to close the gap with enterprise messaging platforms
Krisp
Krisp adds deepfake detection and expands Voice Translation as its Call Center AI platform deepens enterprise compliance tools.
See all Mailu alternatives → · See all Respond.io alternatives →
Recent activity from Mailu and Respond.io
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 13d agoRespond.ioPersistent Online Status While Connected
- 13d agoRespond.ioAI Agents Upgraded to GPT-5.6
- 15d agoRespond.ioReview AI Agent Instructions Before Publishing
- 20d agoRespond.ioGoogle Calendar Integration — View Meetings with Contacts
- 22d agoRespond.ioMissed Call Auto-Follow-Up Template
- 26d agoRespond.ioTikTok Business Messaging Now Available for US Accounts
- 1mo agoMailuRoundcube 1.6.18 bump clears a TLS-config warning
- 1mo agoMailuAutoconfig fix for modern K-9 Mail
- 1mo agoMailuRoundcube 1.6.17 closes two CVEs
- 2mo agoMailuSets X-Forwarded-By in response to a GHSA advisory
- 2mo agoMailuAdmin UI keeps form values on failed submit
- 2mo agoMailuEscapes sieve fields, fixing autoreplies with special characters
Frequently asked questions
What is the difference between Mailu and Respond.io?
They serve adjacent needs but don't currently overlap on shipped themes. Respond.io is currently shipping more aggressively (velocity 7.5 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 Mailu better than Respond.io?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Respond.io is currently shipping more aggressively (velocity 7.5 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 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 Respond.io?
Top Respond.io alternatives in Comms are ranked by recent ship velocity. Browse the "Respond.io alternatives" section above for the current picks, or visit /alternatives/respond-io for the full list with editorial commentary on each.