Features, pricing, and fit
Compare Empathic Voice Interface and Ultravox on voice capabilities, pricing, and fit.
Compare Hume EVI and Ultravox 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.
API-first native speech-language model with a no-code Console, custom tools, and bring-your-own telephony for phone, web, and native apps.
Engineering teams that want direct speech processing and control over telephony or app transports.
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. Ultravox: Pay-as-you-go and Pro plans combine a published per-minute rate with monthly plan fees; Enterprise is custom, and SIP is priced separately. 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 Ultravox, 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. Ultravox: Open weights do not remove hosting, latency, safety, evaluation, voice, and telephony work. Review license and SLA.
Record your requirements and pilot results in the buyer worksheet →
Swipe or scroll the table to see every column.
| Criterion | Empathic Voice Interface | Ultravox |
|---|---|---|
| Provider type | Expressive native voice model API | Native speech-language model API |
| Best fit | Developers evaluating prosody-aware spoken interactions with configurable voices and optional supplemental LLMs. | Engineering teams that want direct speech processing and control over telephony or app transports. |
| Key capabilities | prosody-aware interaction; expressive output; realtime sessions; tools | direct speech-language interaction; open weights; hosted API; tools; realtime sessions |
| 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 | Native speech-language model |
| 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. | Pay-as-you-go and Pro plans combine a published per-minute rate with monthly plan fees; Enterprise is custom, and SIP is priced separately. |
| 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. | 30 free minutes; $0.05/min pay-as-you-go; Pro $100/month; SIP about $0.005/min. |
| Free plan or trial | Free plan includes 5 EVI minutes; confirm the selected EVI version and current terms. | 30 free minutes; open weights under published license. |
| 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. | Ultravox documents a native speech path without a separate ASR stage, then exposes both Console prototyping and REST/SDK integration with BYOT telephony. |
| Considerations | Empathic positioning is not proof of accurate emotion inference. Test false interpretations, cultural variation, consent, sensitive uses, and escalation. | Open weights do not remove hosting, latency, safety, evaluation, voice, and telephony work. Review license and SLA. |
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.
Engineering teams that want direct speech processing and control over telephony or app transports.
Ultravox documents a native speech path without a separate ASR stage, then exposes both Console prototyping and REST/SDK integration with BYOT telephony.
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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