Features, pricing, and fit
Compare Empathic Voice Interface and Line on voice capabilities, pricing, and fit.
Compare Hume EVI and Cartesia Line for AI phone agents, Voice AI platforms, then match channels, workflows, and deployment models to your call flow.
EVI is a speech-to-speech WebSocket API that streams transcripts, vocal-expression measures, assistant text, and response audio.
Developers evaluating prosody-aware spoken interactions with configurable voices and optional supplemental LLMs.
Explore its buying criteria: AI phone agents · Voice AI platforms.
Managed Line runtime for voice agents with no-code Agent Builder, SDK-defined reasoning, Cartesia Ink STT, Sonic TTS, deployment, and observability.
Teams that want managed audio plumbing while retaining code-level control over reasoning, tools, and external APIs.
Explore its buying criteria: AI phone agents · Voice AI platforms.
Both profiles checked 2026-09-04.
Use the table below to compare each provider’s documented scope.
Before you decide
Hume EVI: Monthly plans include EVI minutes; additional EVI 3 usage is billed per minute on Pro, Scale, and Business, while TTS uses separate character allowances and rates. Cartesia Line: Not publicly documented Ask both vendors to quote the same expected workload, required channels, and implementation scope. Include required subscriptions and usage charges before comparing the total; the listed starting prices alone may cover different work.
The recorded knowledge and data sources for Hume EVI include Not publicly documented. For Cartesia Line, they include Not publicly documented. Ask each provider to demonstrate access for the exact systems you use, with permissions, freshness, and failure behavior. A source missing from this directory is not proof that a provider cannot support it.
Use the same representative calls, approved instructions, and escalation rules in both pilots. How does it handle interruption and uncertainty? Which actions can it complete, and which require approval? What context reaches a human during transfer? Record conversation quality, completed tasks, human handoffs, and total cost in the buyer worksheet. Check these specific cautions before launch: Hume EVI: Empathic positioning is not proof of accurate emotion inference. Test false interpretations, cultural variation, consent, sensitive uses, and escalation. Cartesia Line: Confirm product availability, carrier coverage, models, data handling, and generally available features.
Record your requirements and pilot results in the buyer worksheet →
Swipe or scroll the table to see every column.
| Criterion | Empathic Voice Interface | Line |
|---|---|---|
| Provider type | Expressive native voice model API | Voice agent platform and speech API |
| Best fit | Developers evaluating prosody-aware spoken interactions with configurable voices and optional supplemental LLMs. | Teams that want managed audio plumbing while retaining code-level control over reasoning, tools, and external APIs. |
| Key capabilities | prosody-aware interaction; expressive output; realtime sessions; tools | realtime voices; agent configuration; telephony; tools; API |
| Team sizes | startup; mid-market; enterprise; developer | startup; mid-market; enterprise; developer |
| Call surfaces | WebSocket; web; mobile; telephony integrations | phone / PSTN; API / SDK |
| Voice stack | Native speech-to-speech with prosody-sensitive processing | Cascaded STT-LLM-TTS using Cartesia TTS |
| Telephony | Not publicly documented | Not publicly documented |
| Call controls | Not publicly documented | Not publicly documented |
| Languages | Not publicly documented | Not publicly documented |
| Integrations | Not publicly documented | Not publicly documented |
| Knowledge and data | Not publicly documented | Not publicly documented |
| Pricing model | Monthly plans include EVI minutes; additional EVI 3 usage is billed per minute on Pro, Scale, and Business, while TTS uses separate character allowances and rates. | Not publicly documented |
| Pricing signal | EVI 3: Pro $70/month with 1,200 minutes and $0.06/min additional; Scale $200 with 5,000 and $0.05; Business $500 with 12,500 and $0.04. | Approximately $0.06/min plus about $0.014/min managed telephony; verify current calculator. |
| Free plan or trial | Free plan includes 5 EVI minutes; confirm the selected EVI version and current terms. | Not publicly documented |
| What stands out | EVI’s structured WebSocket messages expose both transcript and vocal-expression measures alongside generated text/audio; EVI versions differ in language coverage and supplemental-LLM requirements. | Line separates reasoning from audio operations: it offers a no-code builder or SDK for custom logic while managing deployment/observability and pairing Ink with Sonic. |
| Considerations | Empathic positioning is not proof of accurate emotion inference. Test false interpretations, cultural variation, consent, sensitive uses, and escalation. | Confirm product availability, carrier coverage, models, data handling, and generally available features. |
Developers evaluating prosody-aware spoken interactions with configurable voices and optional supplemental LLMs.
EVI’s structured WebSocket messages expose both transcript and vocal-expression measures alongside generated text/audio; EVI versions differ in language coverage and supplemental-LLM requirements.
Teams that want managed audio plumbing while retaining code-level control over reasoning, tools, and external APIs.
Line separates reasoning from audio operations: it offers a no-code builder or SDK for custom logic while managing deployment/observability and pairing Ink with Sonic.
Verify current pricing, limits, security, and required integrations directly with each provider before purchasing.
Test recognition, speech quality, interruptions, language switching, tool use, and human transfer with your own calls in the required language. Availability can vary by model, plan, and phone route.
DocsBot documents multilingual voice workflows and Japanese support. Verify the exact voice, phone path, and transfer behavior in your pilot. Review DocsBot language information ↗
Other providers’ language claims reflect cited vendor material; confirm Japanese and other required languages directly with each provider.
Listing does not imply endorsement or a performance guarantee. This directory is published by DocsBot. Editorial policy
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