Lead Qualification
Instantly screen inbound contacts, confirm match criteria, and log results.
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A monday.com company
Harmony.ai vs Sierra: managed call qualification, not a CX agent you integrate.
Harmony.ai is a managed voice AI platform for teams handling 500+ calls a month. White-glove implementation, live in days, every call transcribed and scored. Our own models, built for the phone.
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Harmony.ai vs Sierra
 | Sierra | |
|---|---|---|
| Platform | ||
| Built for | Revenue teams: AI receptionist, AI SDR, scheduling | Enterprise customer-experience agents across chat, SMS, WhatsApp, email, voice and ChatGPT |
| Model | Our own models, built for the phone | Routes every turn to the optimal model (published); model providers not named |
| Sounds human | Our own conversation models handle interruptions, timing and tone, so calls feel human | Voice in 55+ languages with mid-conversation switching; handles interruptions and background noise (published) |
| Implementation | White-glove | Customer teams build with Ghostwriter and Agent Studio (no-code) or the Agent SDK (published); deployment timelines not published |
| Calling & scale | ||
| Latency | Sub-200ms median response | Low latency claimed; no figure published |
| Concurrency | 1 to 10,000 parallel calls | Not published |
| Telephony | Built-in telephony or bring your own trunks; buy, assign and retire numbers across regions from one inventory; port or forward | Not published |
| Spam remediation | Number-reputation monitoring, automatic quarantine of flagged numbers, remediation, branded caller ID and local presence | Not published |
| IVR, screeners and gatekeepers | Navigates external phone trees, hold queues and human gatekeepers to reach the right party; DTMF both ways; voicemail detection and retry | Inbound and outbound calls (published); outbound IVR navigation not documented |
| Insight & improvement | ||
| Reporting | Funnel, call-flow and conversation analytics on 100% of calls; ask for a report in plain language and get it built on the spot | AI-driven insights for continuous optimization (published) |
| Self-improvement | Reasoning trace on every call, simulate changes on past calls, agent proposes knowledge-base updates you approve | Voice simulations across edge cases before deploy; AI-driven insights after (published) |
| Experimentation | A/B live or synthetic traffic, publish the winner, roll back; agent keeps what converts across a campaign | Not published |
| Pricing & compliance | ||
| Pricing | Plans start at $3K/month | Outcome-based: pay per completed outcome on a custom enterprise contract; no public rate card (published) |
| Compliance | SOC 2 Type II, HIPAA, GDPR, ISO 27001 | SOC 2, ISO 27001, ISO 42001, HIPAA, GDPR, PCI DSS Level 1 (published) |
Sierra figures from sierra.ai (home, platform and voice pages), checked 12 Oct 2026. Sierra is a trademark of its owner. Harmony.ai is not affiliated with Sierra.
Hear it for yourself.
Three scenarios. One AI agent under pressure.
The interruption test
The caller changes their mind mid-sentence. The agent keeps up, no reset.
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The edge case
An off-script question gets a controlled answer, then straight back to the flow.
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The handoff
When it's genuinely human territory, the agent transfers warm, with a summary.
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Proactive Sales Use Cases
Our agents integrate with your CRM to handle operations across the entire customer lifecycle.
Hear it on your own use case.
Four quick questions, then we’ll configure an agent on your use case and let you listen before you commit to anything.
Why teams choose Harmony.ai over Sierra
Built for revenue, not a toolkit
Inbound and outbound on one platform. The agent dials, qualifies, and books meetings in your CRM.
Implementation is included
White-glove setup, live in days. No engineering project to stand up telephony, models, and workflows.
Every call becomes data
Every call transcribed and scored. Warm transfers with context, PII redaction, TCPA and DNC aware.
Scale without a quota request
1 to 10,000 parallel calls. Sub-200ms median response at any volume.
Meet Siena, your AI assistant
Enterprise-grade security
Enterprise-grade AI infrastructure with built-in protection and security, data privacy, governance, permissions, and compliance.
