Lexicost
AI voice agents / Vendors

Ultravox

In its own words: “We're a research lab and product company dedicated to empowering real-time voice AI experiences.”

9 of 11 key facts published, pages read .

Developer platforms. Hosted, self-serve services that run the whole call: phone numbers, speech, the AI model and call control, usually priced per minute.

What Ultravox publishes, in short. Platform fee per minute: (Pay As You Go). What that fee includes: (Pay As You Go). Monthly plan fee: (Pro). How the AI model is charged: . Every figure below opens Ultravox's own words and the date we read them.

Work out a cost with these figures: billed minutes: how vendors round a call, concurrency limits for AI voice agents, cost per call: AI agent or a person, aI voice agent cost per minute, openAI Realtime API cost per minute. Compare with other vendors in the side by side table.

Price

Platform fee per minutePay As You Go
Platform fee per minutePro
What that fee includesPay As You Go
What that fee includes
What that fee includes
What that fee includes
Monthly plan feePro
How the AI model is charged
How the AI model is charged
US phone minutes
PlanPay As You Go
PlanPro
PlanEnterprise
PlanScale (deprecated)
Minutes includedPay As You Go
Minutes includedPro
AI model rate per million tokensPay As You Go
AI model rate per million tokensPay As You Go
Other phone ratesPay As You Go
Other phone ratesPro
Phone number, per month

Billing rules

How a minute is billed
How a minute is billed
Minimum billed per call
Billing rule
Billing rule
Billing rulePay As You Go and Pro
Billing rule
Billing rule
Billing rule
Billing rule

Capacity

Calls at once, includedPay As You Go
Each extra call at once
When you exceed the limitPay As You Go (no monthly or annual subscription)
When you exceed the limitPro and other paid subscriptions
When you exceed the limitEnterprise
Burst above the limitPro and Enterprise (Pay As You Go: N/A)
Other limits
Other limitsFree / Pay As You Go
Other limitsPro
Other limits
Other limits
Other limits

Getting started

Free credit or trialFree account
Free credit or trial
Sign up without salesPay As You Go and Pro
Sign up without salesEnterprise

Compliance

HIPAA agreement (BAA)Enterprise
SOC 2
SOC 2
Where data is processed
Other compliance statements
Other compliance statements
Other compliance statements
Other compliance statementsEnterprise
Other compliance statements

Product

Latency the vendor states
Bring your own model, voice or carrier
Bring your own model, voice or carrier
White label for agencies
Uptime commitmentEnterprise
Support by plan
Support by plan
Support by plan

Where Ultravox's own pages say different things

Both statements are quoted with their pages. We do not pick one. Ask the vendor which applies before you rely on either.

What Ultravox's public pages do not settle

  • .

What changed

  • 1 Oct 2026. The terms on ultravox.ai became the Inworld AI Terms of Service (Theai, Inc. dba Inworld AI) source
  • 30 Sep 2026. Inworld acquired Ultravox; built-in Inworld voices on Ultravox moved to Realtime TTS-2 at no additional cost source
  • 3 Dec 2025. Default model to switch to Ultravox v0.7 (GLM 4.6) on December 22, 2025, with the price kept at $0.05 per minute (was Llama 3.3 70B default model at $0.05 per minute, now GLM 4.6 default model at $0.05 per minute) source
  • 4 Sep 2024. Per-minute price reduced to $0.05 source

Pages we read

Lexicost has no commercial relationship with any vendor named on this site. Spotted an error? See corrections.

Source for every vendor figure on this page (65)
  1. Ultravox, platform fee per minute: $0.05 per minute after 30 free minutes (Pay As You Go. pay as you go. after the first 30 free minutes).First 30 minutes free, $0.05/min after that. ultravox.ai/pricing Read 14 Nov 2026.
  2. Ultravox, platform fee per minute: $0.05 per minute (Pro).Price Per Minute $0.05 per minute $0.05 per minute Custom ultravox.ai/pricing Read 14 Nov 2026.
  3. Ultravox, what that fee includes: Includes the voice (text-to-speech) (Pay As You Go).5¢ per minute (including TTS) for up to 5 concurrent calls. ultravox.ai Read 14 Nov 2026.
  4. Ultravox, what that fee includes: Speech understanding and generation included (Ultravox v0.7 model on Ultravox Realtime).We’re also keeping the cost of using v0.7 on Ultravox Realtime (our platform for building and scaling voice AI agents) the same at $.05/min. That’s state-of-the-art model performance with speech understanding and speech generation (including ElevenLabs and Cartesia voices) for a price that is half the cost of most providers. ultravox.ai/blog/introducing-ultravox-v0-7-the-world-s-smartest-speech-understanding-model Read 14 Nov 2026.
  5. Ultravox, what that fee includes: No separate speech-to-text stage.There’s no automatic speech recognition (ASR) stage, making conversations faster and more context-aware. docs.ultravox.ai/gettingstarted/how-ultravox-works Read 14 Nov 2026.
  6. Ultravox, what that fee includes: SIP minutes charged on top (SIP calls).Consequently, SIP calls incur costs for SIP minutes in addition to the regular cost of call minutes. docs.ultravox.ai/telephony/sip Read 14 Nov 2026.
  7. Ultravox, monthly plan fee: Pro: $100 per month when billed yearly (Pro. annual (billed yearly)).$100/month *when billed yearly ultravox.ai Read 14 Nov 2026.
  8. Ultravox, plan: Pay As You Go: $0 per month, pay as you go with some hard limits (Pay As You Go. pay as you go).Perfect for just starting out and experimenting. Pay as you go with some hard limits. $0 /month ultravox.ai/pricing Read 14 Nov 2026.
  9. Ultravox, plan: Pro: $100 per month at the annual rate, without hard concurrency caps (Pro. annual rate. the page header says prices are marked as annual rate).Good bye hard concurrency caps. Everything you need to start scaling your Voice AI business. $100 /month ultravox.ai/pricing Read 14 Nov 2026.
  10. Ultravox, plan: Enterprise: custom plan and pricing (Enterprise).Designed for massive scale, we'll work with you to outline a plan that meets your needs. Custom ultravox.ai/pricing Read 14 Nov 2026.
  11. Ultravox, plan: Scale: deprecated and no longer offered; Scale customers can move to Inworld's Growth tier (Scale (deprecated)).†The Scale plan is deprecated and no longer offered. Customers on Scale can migrate to Inworld’s Growth tier. docs.ultravox.ai/gettingstarted/concurrency Read 14 Nov 2026.
  12. Ultravox, minutes included: 30 free minutes (Pay As You Go).30 minutes of free calls ultravox.ai/pricing Read 14 Nov 2026.
  13. Ultravox, minutes included: 30 free minutes (Pro).Free included minutes 30 30 Custom ultravox.ai/pricing Read 14 Nov 2026.
  14. Ultravox, how the AI model is charged: Included in the $0.05 per minute (main conversation; background threads are billed per token).Same Great Price → Stays at our standard $0.05 per minute rate. Better model, same price. docs.ultravox.ai/changelog/news Read 14 Nov 2026.
  15. Ultravox, how the AI model is charged: Threads: per token; cached input free (Threads (parallel agent conversations during a call)).Threads may increase the cost of a call based on their additional model usage. Invoking tools is free. Generations are charged using traditional token-based pricing, except that cached input tokens are free. docs.ultravox.ai/agents/threads Read 14 Nov 2026.
  16. Ultravox, aI model rate per million tokens: Threads: $2.00 per 1M uncached input tokens (Pay As You Go. Threads only; cached input tokens are not charged).$2.00 per 1M input tokens (uncached) ultravox.ai/pricing Read 14 Nov 2026.
  17. Ultravox, aI model rate per million tokens: Threads: $15.00 per 1M output tokens (Pay As You Go. Threads only).$15.00 per 1M output tokens ultravox.ai/pricing Read 14 Nov 2026.
  18. Ultravox, uS phone minutes: Not publicly listed. Read 14 Nov 2026.
  19. Ultravox, other phone rates: SIP: 0.5¢ per minute (Pay As You Go. SIP calls).SIP Pricing .5¢ per minute .48¢ per minute Custom ultravox.ai/pricing Read 14 Nov 2026.
  20. Ultravox, other phone rates: SIP: 0.48¢ per minute (Pro. SIP calls).SIP Pricing .5¢ per minute .48¢ per minute Custom ultravox.ai/pricing Read 14 Nov 2026.
  21. Ultravox, phone number, per month: Not publicly listed. Read 14 Nov 2026.
  22. Ultravox, how a minute is billed: Per 6 seconds: $0.005 each (call minutes at the standard $0.05 per minute rate).Calls are rounded to the nearest “deciminute” (every six seconds). This means that we effectively bill our standard $0.05 per minute rate as $0.005 for every six seconds of call time. docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  23. Ultravox, how a minute is billed: SIP minutes: billed per 6 seconds, rounded up (SIP minutes).Like call minutes, SIP minutes are billed per-deciminute (i.e. six second increments), rounded up to the nearest deciminute. docs.ultravox.ai/telephony/sip Read 14 Nov 2026.
  24. Ultravox, minimum billed per call: A 1-second call is billed as 6 seconds (call minutes).0 0 $0.000 1 6 $0.005 docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  25. Ultravox, billing rule: All calls are rounded up to the nearest deciminute (6 seconds) (call minutes).Finally, all calls are rounded up to the nearest deciminute. docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  26. Ultravox, calls at once, included: Up to 5 calls at once (Pay As You Go).Up to 5 concurrent calls ultravox.ai/pricing Read 14 Nov 2026.
  27. Ultravox, each extra call at once: Not publicly listed. Read 14 Nov 2026.
  28. Ultravox, when you exceed the limit: Above 5 calls, new calls are refused at once with HTTP 429 (Pay As You Go (no monthly or annual subscription)).Any account not on a monthly or annual subscription is limited to five concurrent calls. Any attempt to create additional calls above the hard cap will result in an immediate HTTP 429 “Too Many Requests” response, allowing you to implement proper retry logic and queue management in your application. docs.ultravox.ai/gettingstarted/concurrency Read 14 Nov 2026.
  29. Ultravox, when you exceed the limit: Paid plans: under extreme load a new call may be refused with HTTP 429 (Pro and other paid subscriptions).Our goal is to dynamically match compute with demand, but during periods of extremely high load, it’s possible that we might not have compute available to serve your call. When that happens, we’ll issue an HTTP 429 status code (“Too Many Request”) so you know to try again after a short wait. docs.ultravox.ai/gettingstarted/concurrency Read 14 Nov 2026.
  30. Ultravox, when you exceed the limit: Enterprise: priority for an agreed number of calls at once (Enterprise).Enterprise customers can get priority in the system for an agreed number of concurrent calls (contact us to discuss). docs.ultravox.ai/gettingstarted/concurrency Read 14 Nov 2026.
  31. Ultravox, burst above the limit: No surge pricing (Pro and Enterprise (Pay As You Go: N/A)).Surge Pricing N/A Never Never ultravox.ai/pricing Read 14 Nov 2026.
  32. Ultravox, other limits: API requests: 500 per second per account, 200 per second per API key.Account 500 API Key 200 docs.ultravox.ai/api-reference/introduction Read 14 Nov 2026.
  33. Ultravox, other limits: New calls: 5 per second and 30 per minute (Free / Pay As You Go).Free / PAYGO 5 30 docs.ultravox.ai/api-reference/introduction Read 14 Nov 2026.
  34. Ultravox, other limits: New calls: 10 per second and 120 per minute (Pro).Pro 10 120 docs.ultravox.ai/api-reference/introduction Read 14 Nov 2026.
  35. Ultravox, other limits: Knowledge bases (RAG corpora): 2 on Pay As You Go, 20 on Pro, custom on Enterprise.Number of Corpora (RAG) 2 20 Custom ultravox.ai/pricing Read 14 Nov 2026.
  36. Ultravox, other limits: Hard cap on calls at once: 5 on Pay As You Go; none on Pro or Enterprise.Hard Cap on Concurrent Calls 5 No No ultravox.ai/pricing Read 14 Nov 2026.
  37. Ultravox, other limits: Custom voice clones: 1 on Pay As You Go, 5 on Pro, custom on Enterprise (pricing page).Custom Voice Clones 1 5 Custom Also: Currently, we support one cloned voice per account. If you need more cloned voices, please reach out. docs.ultravox.ai/voices/cloning ultravox.ai/pricing Read 14 Nov 2026.
  38. Ultravox, free credit or trial: 30 free minutes of calls on a new account (Free account).You can sign-up for a free account that comes with 30 free minutes for creating calls. docs.ultravox.ai/api-reference/introduction Read 14 Nov 2026.
  39. Ultravox, free credit or trial: Calls made in the console playground are free (calls made in the agent builder in the web console).These are calls that you make in the agent builder using the web console application. There is no charge for these calls and we encourage you to make use of this feature to thoroughly test your agents before deploying them. docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  40. Ultravox, sign up without sales: Yes: sign up online in the console (Pay As You Go and Pro).Don’t have an account? Sign up app.ultravox.ai Read 14 Nov 2026.
  41. Ultravox, sign up without sales: Enterprise: plan worked out with Ultravox (Enterprise).Designed for massive scale, we'll work with you to outline a plan that meets your needs. ultravox.ai/pricing Read 14 Nov 2026.
  42. Ultravox, hIPAA agreement (BAA): BAA on an Enterprise plan (Enterprise).We sign Business Associate Agreements (BAAs) for customers with HIPAA needs, on an Enterprise plan. You can also remove call data after each call (see below). Contact support@inworld.ai to discuss your requirements. docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  43. Ultravox, sOC 2: SOC 2 Type I: compliant.SOC 2 Type I Compliant trust.delve.co/ultravox Read 14 Nov 2026.
  44. Ultravox, sOC 2: SOC 2 Type II: in progress.SOC 2 Type II In Progress trust.delve.co/ultravox Read 14 Nov 2026.
  45. Ultravox, where data is processed: Not publicly listed. Read 14 Nov 2026.
  46. Ultravox, other compliance statements: HIPAA: in progress.HIPAA In Progress trust.delve.co/ultravox Read 14 Nov 2026.
  47. Ultravox, other compliance statements: GDPR: in progress.GDPR In Progress trust.delve.co/ultravox Read 14 Nov 2026.
  48. Ultravox, other compliance statements: Call data is kept until you delete it.Call data is retained until you delete it. docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  49. Ultravox, other compliance statements: Enterprise: automatic deletion of call data after each call (Enterprise).Customers on an Enterprise plan can also set a retentionPolicy on calls (for example, in Create Call) so that call data (summaries, transcripts and recordings) is deleted automatically after the call, with no deletion calls needed. docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  50. Ultravox, other compliance statements: The contract is with Theai, Inc. dba Inworld AI (terms effective October 1, 2026).These Terms of Service ("Terms") form a legally binding agreement between you ("Customer," "you," or "your") and Theai, Inc. dba Inworld AI ("Inworld AI," "we," "our," or "us"). ultravox.ai/terms Read 14 Nov 2026.
  51. Ultravox, latency the vendor states: Not publicly listed. Read 14 Nov 2026.
  52. Ultravox, bring your own model, voice or carrier: Bring your own telephony: SIP trunking, Twilio or other providers.Ultravox is designed as a bring-your-own-telephony platform, giving you complete flexibility in how you connect voice AI to your users (inbound or outbound). Whether you’re using SIP trunking, Twilio, or any other telephony provider, Ultravox seamlessly integrates with your existing infrastructure. docs.ultravox.ai/gettingstarted/how-ultravox-works Read 14 Nov 2026.
  53. Ultravox, bring your own model, voice or carrier: Bring your own text-to-speech provider (ElevenLabs, Cartesia, OpenAI and others).Ultravox Realtime allows you to bring your own TTS provider to have your agent sound however you like. docs.ultravox.ai/voices/bring-your-own Read 14 Nov 2026.
  54. Ultravox, white label for agencies: Not publicly listed. Read 14 Nov 2026.
  55. Ultravox, uptime commitment: Enterprise: priority SLA (Enterprise).Priority SLA ultravox.ai/pricing Read 14 Nov 2026.
  56. Ultravox, support by plan: Response SLA: Enterprise only.Response SLA No No Yes ultravox.ai/pricing Read 14 Nov 2026.
  57. Ultravox, support by plan: Org support: Enterprise only (custom).Org Support No No Custom ultravox.ai/pricing Read 14 Nov 2026.
  58. Ultravox, support by plan: Support, billing and enterprise questions by email to support@inworld.ai; community help on Discord.For product support issues, billing questions, or inquiries about custom enterprise plans, reach out to us directly at: support@inworld.ai docs.ultravox.ai/gettingstarted/getting-help Read 14 Nov 2026.
  59. Ultravox, billing rule: Usage is invoiced monthly in arrears; the Pro subscription is billed in advance.We send out monthly invoices to bill for usage (calls and SIP) in the prior period (AKA billing in arrears). If you are a Pro plan subscriber, we bill you at the beginning of each period to cover your subscription usage in advance. docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  60. Ultravox, billing rule: An early bill is sent when usage passes $10 (Pay As You Go) or $100 (Pro) (Pay As You Go and Pro).Pay as you go (PAYGO) and Pro plan customers may also receive bills before the regular monthly cycle if usage exceeds the set threshold ($10 for PAYGO, $100 for Pro plan). docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  61. Ultravox, billing rule: Billed time runs on the call clock, so it can exceed the recording length.Billing duration is based on the clock that is running for the entire length of the call. Depending on your setup, there may be overhead incurred before Ultravox receives any user audio (this would mean billed duration > call recording). docs.ultravox.ai/gettingstarted/faq Read 14 Nov 2026.
  62. Ultravox, billing rule: SIP minutes can be billed while the agent is not connected (for example transfer legs); ringing is not billed (SIP calls).Unlike call minutes, SIP minutes can be billed even when your agent is not connected to a user — for example, transfer legs that keep running after your agent leaves the call. Ringing time is not billed though: an outgoing call only begins accruing SIP minutes once it is answered, so a call that is never answered incurs no SIP minutes. docs.ultravox.ai/telephony/sip Read 14 Nov 2026.
  63. Ultravox, billing rule: Bridged transfers: SIP minutes accrue at double rate while both legs are active (SIP calls with bridged cold transfer).Bridged cold transfer: A second call leg is created for the transfer target, so SIP minutes accumulate at double the normal rate while both calls are active. If the transfer is accepted, both legs remain active and continue billing even after the agent leaves the call. docs.ultravox.ai/telephony/sip Read 14 Nov 2026.
  64. Ultravox, billing rule: Subscriptions can be cancelled at any time; payments are non-refundable unless the law requires.Cancellation. You can cancel your paid subscription at any time. Payments are non-refundable, except where required by law. ultravox.ai/terms Read 14 Nov 2026.
  65. Ultravox, where the vendor's own pages disagree: The pricing page lists 5 custom voice clones on Pro, while the voice cloning docs say one cloned voice per account. (Pro).Custom Voice Clones 1 5 Custom Also: Currently, we support one cloned voice per account. If you need more cloned voices, please reach out. docs.ultravox.ai/voices/cloning ultravox.ai/pricing Read 14 Nov 2026.