Ultravox vs Vapi (2026): which should you pick?

Pick Ultravox if

• Fits if you are a developer who wants one model that listens and speaks
• Makes sense if you will pay by the minute and build your own call flow

Look elsewhere if

• Not for you if you want a no-code builder: it is APIs and SDKs
• Watch out: the site says Ultravox has been acquired by Inworld, and plans and pricing may change
• Tight if you scale on Pay as You Go: it is capped at 5 concurrent calls
• Watch out: the pricing page marks prices as an annual rate and shows no monthly-billed price

Pick Vapi if

• Fits if you are a developer who wants to choose each voice and model provider
• Makes sense if you want to pay for minutes as you use them

Look elsewhere if

• Pricey if you want one price, as model, voice and call charges sit on top of the $0.05 hosting
• Watch out: HIPAA-eligible handling is a $2,000 a month add-on
• Pricey if you grow, since Pro has a $999 a month minimum
• Watch out: extra lines cost $10 each and extra organisations $20 each a month

Ultravox

• The site announces that Ultravox has been acquired by Inworld; future plans and pricing may change.
• The pricing page marks prices as an annual rate; a monthly-billed price is not shown.
• Pay as You Go is capped at 5 concurrent calls.
• Threads pricing is $2.00 per 1M uncached input tokens and $15.00 per 1M output tokens.

Vapi

• Without a success package, hosting is $0.05 per minute, pre-paid, and Deepgram, model and voice costs are added on top; the page's 1,000-minute estimate is $82 to $129 a month.
• HIPAA-eligible data handling is a $2,000 per month add-on.
• Extra concurrent lines cost $10 per line per month and extra organizations $20 per organization per month.
• Twilio, Vonage and Telnyx call charges are billed by those providers, such as $0.008 per minute for Twilio inbound.

Ultravox

Speech-native model

Processes audio directly so tone and cadence are not lost in transcription, and the vendor runs its own inference stack.

REST APIs and SDKs

Developer APIs plus kits for web and mobile platforms.

Telephony

Built-in telephony support, with SIP calls priced from about half a cent per minute.

Outbound call scheduler

Schedules outbound calls; available on Pro and Enterprise.

RAG corpora

Attach knowledge corpora to an agent: 2 on Pay as You Go and 20 on Pro.

Vapi

Voice agent orchestration

Configure voice, conversation flow, telephony and integrations for an agent, then deploy it behind a phone number or an API.

Choice of providers

The pricing calculator lets you pick the transcriber, language model and voice, for example Deepgram, OpenAI and ElevenLabs. Models are passed through at cost.

Testing and simulation

Calls can be simulated before they reach customers, and monitoring flags issues in live calls.

Telephony options

Vapi telephony and SIP, WebSockets and Daily WebRTC are listed as free transport; Twilio, Vonage and Telnyx are charged by those providers.

Enterprise controls

The site lists SSO, OAuth, RBAC and AI guardrails, and says SOC 2, HIPAA and PCI compliance are supported.

Ultravox

• Pay as You Go$0

  per month, plus $0.05 per minute

  30 free minutes, then 5 cents a minute; up to 5 concurrent calls and 2 RAG corpora.

• Pro$100

  per month, billed yearly

  No hard cap on concurrency, outbound call scheduler, 5 custom voices and 20 RAG corpora.

• EnterpriseCustom

  Priority SLA, org support and customizable limits.

Vapi

• Core$29

  per month, pre-paid, auto-renew

  2 organizations, 5 included phone numbers, 10 concurrent calls, 30 days of raw data retention and email support.

• Pro$999

  per month minimum, 10% of the hosting fee

  10 organizations, 30 concurrent calls, 180 days retention, RBAC, a dedicated Slack channel and a 99% uptime SLA.

• PremierCustom

  Direct sales only: higher limits, named support team, 99.9% uptime SLA, SSO and dedicated SIP.