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Voice and conversational AI · Voice agent platforms for builders

Retell AI

Developer platform for voice agents with low latency, built-in telephony and per-minute pricing.

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Our pick for voice agent platforms for builders
Vendor
Retell AI
Pricing model
Pay as you go per minute: voice engine plus your chosen LLM and voice; no platform fee.
Runs on
Retell cloud
Agentic OS layer
Agents
Industries
Any industry
Last reviewed
November 2026

Our verdict

A strong default for building phone agents: fast, natural turn-taking, built-in telephony and no platform fee. The model you choose drives most of the cost.

What it is

Retell provides voice infrastructure for inbound and outbound phone agents: speech, turn-taking, interruptions, telephony, knowledge bases, call transfer and analytics, with an API and a visual builder.

Pricing stacks the voice engine, the LLM and text-to-speech per minute; add-ons such as knowledge base and denoising cost extra.

Best for

Product and operations teams building scheduling, intake, qualification and support calls.

Not the right fit

Enterprises that want a fully managed service and brand voice design.

Key capabilities

Low-latency voice

Natural interruption handling.

Built-in telephony

Numbers, SIP and transfers.

Builder and API

Visual flows or code.

Analytics and QA

Call review and quality checks.

Strengths

  • No platform fee
  • Transparent per-minute pricing
  • Fast to prototype and deploy

Watch-outs

  • LLM choice can triple the per-minute cost
  • Add-ons stack per minute
  • You own design and quality

Pricing

Retell lists $0.07 to $0.31 per minute for voice agents on pay as you go. The voice engine is $0.055 per minute; LLM and voice add more, with frontier models costing several times the engine fee. Phone numbers are about $2 a month and extra concurrency $8 per line. Enterprise is quoted.

Checked November 2026. Vendors change plans often, so confirm current pricing with Retell AI before you budget.

Security and governance

SOC 2, HIPAA support and PII removal options.

How we would roll it out

  1. Pick the cheapest model that worksTest smaller models first.
  2. Script transfers to humansClear exits protect customers.
  3. Review calls weeklyFix prompts from real transcripts.

Compare with

Other tools in Voice and conversational AI, closest match first.

Vapi

Voice agent platforms for builders

Voice agent orchestration for developers who bring their own speech, model and telephony providers.

Best for Engineers who want full control of every voice component.

$0.05/min platform + providersRead review

ElevenLabs Agents

Voice agent platforms for builders

Conversational agents on ElevenLabs voices, across phone, web, chat and email.

Best for Teams that put voice quality and languages first.

$0.08/min + LLM and telephonyRead review

PolyAI

Managed enterprise voice

Our pick

Enterprise voice agents for contact centres, delivered as a managed service on its own dialog models.

Best for Large contact centres that want lifelike voice agents without building them.

Quote only, per minuteRead review
Implementing Retell AI? Our Conversational and Voice AI team designs, builds and governs it inside your stack. We take no partner fees, so the review above stays independent.See Conversational and Voice AI

More in Voice and conversational AI · How we govern agents · How an engagement runs

Choosing between Retell AI and the alternatives?

Book a call. We look at your systems, data and governance together and tell you which platform fits, and what to build on it first.

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