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Comparison · Comms
OpenPhone vs Stalwart
A side-by-side editorial comparison of OpenPhone and Stalwart — release velocity, themes, recent moves, and the top alternatives to consider.
OpenPhone vs Stalwart: at a glance
| Feature | OpenPhone | Stalwart |
|---|---|---|
| Sector | Comms | Comms |
| Velocity score | 0.0 | 6.3 |
| Sparks · 30d | 0 | 1 |
| Top themes | business voip, ai phone agent, call routing, smb communication | email-server, scim, jmap, enterprise-provisioning |
| Last editorial update | 4mo ago | 17d ago |
| Website | — | Visit → |
What is OpenPhone?
OpenPhone turns Sona into a deployable front-line AI agent with transfers and per-scenario instructions.
OpenPhone is hardening Sona, its AI phone agent, into something businesses can actually put in front of customers. Sona can now route calls to the right teammate when a human is needed, and admins can give it custom instructions per scenario (lead qualification, cancellations, booking) with templates to start from. Around it, the call flow builder keeps maturing: multiple routing setups with quick switching, in-place inbox switching during flow construction, and a Go-to Step primitive for cleaner branches.
What is Stalwart?
Stalwart adds full SCIM v2 provisioning and 24-language calendar support as its standards coverage extends further than most commercial mail servers.
Stalwart is maintaining a weekly-or-faster release cadence, with alternating feature releases and dense bug-fix releases. The v0.16.20 release landed full SCIM v2 (Enterprise) including cursor-based pagination and the IPSIE lifecycle profile, conference links in calendar invites, and 24 new calendar interface translations. Below the feature line, the project is steadily closing correctness gaps across JMAP, CalDAV, IMAP, and MTA — many of them edge-case RFC compliance issues.
OpenPhone vs Stalwart: editorial side-by-side
OpenPhone
0.0COMMS
OpenPhone turns Sona into a deployable front-line AI agent with transfers and per-scenario instructions.
◆ Current state
OpenPhone is hardening Sona, its AI phone agent, into something businesses can actually put in front of customers. Sona can now route calls to the right teammate when a human is needed, and admins can give it custom instructions per scenario (lead qualification, cancellations, booking) with templates to start from. Around it, the call flow builder keeps maturing: multiple routing setups with quick switching, in-place inbox switching during flow construction, and a Go-to Step primitive for cleaner branches.
◆ Where it's heading
The core bet is an AI-handles-first-contact, humans-handle-edge-cases pattern. Each Sona release is closing a deployment-blocker (instructions, transfers, free trial), while the call-flow tooling underneath is getting more flexible so AI and human routing can coexist in one config. Plan-tier expansion (call hold on Starter) suggests OpenPhone is also chasing volume in the lower segment.
◆ Prediction
Expect Sona to gain CRM-aware context (caller history, deal state) and outbound use cases — proactive callbacks, scheduled follow-ups. Pricing for Sona usage is likely to evolve from a flat add-on toward usage- or outcome-based once volume appears.
Stalwart
6.3COMMS
Stalwart adds full SCIM v2 provisioning and 24-language calendar support as its standards coverage extends further than most commercial mail servers.
◆ Current state
Stalwart is maintaining a weekly-or-faster release cadence, with alternating feature releases and dense bug-fix releases. The v0.16.20 release landed full SCIM v2 (Enterprise) including cursor-based pagination and the IPSIE lifecycle profile, conference links in calendar invites, and 24 new calendar interface translations. Below the feature line, the project is steadily closing correctness gaps across JMAP, CalDAV, IMAP, and MTA — many of them edge-case RFC compliance issues.
◆ Where it's heading
Stalwart is building toward parity with commercial enterprise mail servers on identity federation and provisioning (SCIM v2, VAPID for web push, DMARCbis/DKIM2 already landed). The pace of RFC implementation is unusually aggressive for an open-source project; the combination of JMAP, CalDAV, IMAP UIDONLY/UIDBATCHES, and SCIM v2 positions it as a viable self-hosted alternative for organizations that need standards compliance without vendor lock-in.
◆ Prediction
WebAuthn/passkey-based authentication and improved multi-tenant administration tooling are the most likely next capability additions, given the current trajectory toward enterprise identity management.
Alternatives to OpenPhone and Stalwart
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 OpenPhone or Stalwart.
Twilio
Twilio embeds full omnichannel routing into Salesforce, moving beyond raw API consumers.
Netcore Cloud
Netcore launches Cori, an AI marketing agent that monitors channels and finds revenue gaps automatically.
Tawk.to
tawk.to ships a programmable widget API and AI assistant improvements while maintaining its free-forever positioning.
Salesmsg
Salesmsg deepens HubSpot automation while AI agents gain autonomous action across text and calling
FluentBooking
FluentBooking opens bookings to AI agents via MCP, then ships workflow ergonomics
See all OpenPhone alternatives → · See all Stalwart alternatives →
Recent activity from OpenPhone and Stalwart
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 19d agoStalwartv0.16.21
- 26d agoStalwartv0.16.20 ⚡
- 1mo agoStalwartv0.16.19
- 1mo agoStalwartv0.16.18
- 1mo agoStalwartv0.16.17
- 1mo agoStalwartv0.16.16
- 1y agoOpenPhoneCall hold now available on Starter plan
- 1y agoOpenPhoneTransfer calls from Sona to your team ⚡
- 1y agoOpenPhoneControl how Sona responds in different situations
- 1y agoOpenPhoneCreate multiple call flows, and switch back and forth easily
- 1y agoOpenPhoneImproved navigation for call flow building
- 1y agoOpenPhoneBuild cleaner call flows with the Go-to Step feature
Frequently asked questions
What is the difference between OpenPhone and Stalwart?
They serve adjacent needs but don't currently overlap on shipped themes. Stalwart is currently shipping more aggressively (velocity 6.3 vs 0.0), with 1 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 OpenPhone better than Stalwart?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Stalwart is currently shipping more aggressively (velocity 6.3 vs 0.0), with 1 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 OpenPhone?
Top OpenPhone alternatives in Comms are ranked by recent ship velocity. Browse the "OpenPhone alternatives" section above for the current picks, or visit /alternatives/openphone for the full list with editorial commentary on each.
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.