Features, pricing, and fit
Compare Ultravox and Voice Agent API on voice capabilities, pricing, and fit.
Compare Ultravox and Deepgram Voice Agent for AI phone agents, Voice AI platforms, then match channels, workflows, and deployment models to your call flow.
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.
Unified Voice Agent API that combines Deepgram speech recognition, LLM orchestration, and voice synthesis with function calling and mid-session controls.
Developers who want one managed voice API instead of assembling separate STT, orchestration, and TTS services.
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
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. Deepgram Voice Agent: Usage-based per-hour API pricing; the product page publishes $4.50/hour, with telephony separate. 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 Ultravox include Not publicly documented. For Deepgram Voice Agent, 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: Ultravox: Open weights do not remove hosting, latency, safety, evaluation, voice, and telephony work. Review license and SLA. Deepgram Voice Agent: Telephony and complete workflow operations are not implied. Confirm languages, concurrency, pass-through charges, observability, and data controls.
Record your requirements and pilot results in the buyer worksheet →
Swipe or scroll the table to see every column.
| Criterion | Ultravox | Voice Agent API |
|---|---|---|
| Provider type | Native speech-language model API | Voice agent API and speech infrastructure |
| Best fit | Engineering teams that want direct speech processing and control over telephony or app transports. | Developers who want one managed voice API instead of assembling separate STT, orchestration, and TTS services. |
| Key capabilities | direct speech-language interaction; open weights; hosted API; tools; realtime sessions | managed runtime; speech recognition; speech synthesis; bring-your-own LLM; functions |
| Team sizes | startup; mid-market; enterprise; developer | startup; mid-market; enterprise; developer |
| Call surfaces | phone / PSTN; API / SDK | WebSocket; web; mobile; telephony integrations |
| Voice stack | Native speech-language model | Cascaded STT-LLM-TTS managed full stack |
| 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 | 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. | Usage-based per-hour API pricing; the product page publishes $4.50/hour, with telephony separate. |
| Pricing signal | 30 free minutes; $0.05/min pay-as-you-go; Pro $100/month; SIP about $0.005/min. | $4.50/hour, equivalent to $0.075/min, plus telephony. |
| Free plan or trial | 30 free minutes; open weights under published license. | Not publicly documented |
| What stands out | Ultravox documents a native speech path without a separate ASR stage, then exposes both Console prototyping and REST/SDK integration with BYOT telephony. | Deepgram’s documented API puts STT, LLM orchestration, TTS, barge-in, turn-taking, function calling, and session control behind one interface. |
| Considerations | Open weights do not remove hosting, latency, safety, evaluation, voice, and telephony work. Review license and SLA. | Telephony and complete workflow operations are not implied. Confirm languages, concurrency, pass-through charges, observability, and data controls. |
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.
Developers who want one managed voice API instead of assembling separate STT, orchestration, and TTS services.
Deepgram’s documented API puts STT, LLM orchestration, TTS, barge-in, turn-taking, function calling, and session control behind one interface.
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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