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Intervo AI vs Retell AI

Two fact sheets from our own research, side by side — pricing, platforms, API access and status re-checked by us rather than quoted from the vendors. Intervo AI starts at $10, Retell AI at $0.07. Both have a free tier. Both ship a public API.

Intervo AIOpen-source builder for voice and chat agents that answer calls, qualify leads and book meetings.Retell AIBuild and run AI phone agents that book, qualify and transfer calls, billed by the minute.

Side by side

FactIntervo AIRetell AI
CategoryVoice Agents & Phone AIVoice Agents & Phone AI
Pricing modelFreemiumFreemium
Starts at$10 one_time$0.07 minute
Public APIYesYes
PlatformsWeb, APIWeb, API
CompanyCodedesign, Inc.Retell AI Inc.
Launched—2023
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

Intervo AI

One of the few voice agent platforms where you can read the source and move the whole thing in-house if the hosted pricing turns against you. Model and voice vendors are swappable rather than locked, which keeps per-minute costs negotiable. The catch is that the headline monthly price is quoted against a struck-through number, which is a discount that has been running long enough to be the real price.

Pros

  • Source is public on GitHub, so self-hosting is a real fallback rather than a promise
  • Model provider and voice engine are picked independently, covering OpenAI, Anthropic, Google, ElevenLabs and Azure
  • Integrations cover Intercom, Zapier, Google Sheets, Cal.com and generic webhooks out of the box
  • A free tier with three agents makes evaluation possible without a card

Cons

  • The 129 USD plan is displayed as a permanent discount off a much larger list price, so the real anchor is unclear
  • No country or registered address is published for Codedesign, Inc.
  • Self-hosting shifts integration, security and compliance costs onto you, as the vendor itself notes
  • Stated 90 to 95 percent accuracy is vendor-reported and conditioned on ideal audio

Retell AI

One of the more honest voice-agent stacks: the pricing page breaks out infrastructure, TTS and LLM cost per minute so you can predict a call's cost instead of guessing. Telephony choice is wide and the concurrency allowance is generous. The catch is that per-minute billing plus add-ons makes a busy contact centre expensive fast, and the cheap end of the range only holds if you pick the cheap models.

Pros

  • Per-minute cost broken down by voice infrastructure, TTS provider and LLM on the public pricing page
  • Telephony via SIP trunking, Twilio and Vonage plus n8n, HubSpot, Make and Go High Level integrations
  • 20 concurrent calls included before any concurrency charge
  • Voice, chat and SMS agents share one platform and API
  • HIPAA path exists via a signed BAA covered in the terms of service

Cons

  • Cost per minute more than quadruples between the cheapest and most capable model combinations
  • Knowledge base, denoising, PII removal and branded caller ID are all metered extras
  • No flat-rate plan, so a spike in call volume lands straight on the invoice

Which one fits

Choose Intervo AI if you need

  • Agencies deploying the same agent template across many client accounts
  • Teams that want an exit route via self-hosting rather than vendor lock-in
  • Businesses needing calls handled in more than one language

Choose Retell AI if you need

  • Teams replacing an outbound qualification or booking script
  • Contact centres that already have Twilio, Vonage or SIP trunking
  • Developers who want per-minute cost visibility before launch

More comparisons

All Intervo AI alternatives →Browse all Voice Agents & Phone AI →