Retell

What it is for

Retell is a pay-as-you-go voice-agent studio: you create an agent from a template or a prompt, test it, then attach a number. Use it when the job is a phone or chat agent billed by the minute, not when you need a TTS download.

It is not open source. Sign-up starts at $0; you pay for connected minutes (infra $0.055/min plus the voice and LLM you pick).

What makes it unique: the cover is Retell’s official Create-agent dialog — Single prompt vs Conversational flow, Generate from prompt, and templates (Insurance Verification, IVR, Outreach) — not a call-center illustration.

Key features

• Create from a template or a prompt — Receptionist, Outbound Sales, Appointment Booking, Lead Qualification, or Generate from prompt (cover; Pricing).
• Single prompt vs Conversational flow — free-form vs a deterministic production flow (cover).
• Simulation testing — run the agent before it hits a customer (Pricing).
• Call analytics and transcripts — included on pay-as-you-go (Pricing).
• 20 free concurrent calls — extra concurrency is $8 / concurrent / month (Pricing).
• Webhooks and API — full platform access on the $0 usage path; no feature gate vs Enterprise except compliance / support (Pricing).

Who it's for

Best fit: teams that want a voice agent today and will pay minutes + add-ons, without an annual commit.

Poor fit: buyers who want one all-in minute that already includes the LLM (Bland).

Pricing

Verified 2026-10-22 (Asia/Shanghai) from retellai.com/pricing. The comparison table prints $0.07–$0.31/minute all-in. The estimator example we fetched totaled $0.11/min (LLM $0.04 + infra $0.055 + TTS $0.015). Re-check the toggle.

• Pay-as-you-go — $0 to start. Retell Voice Infra $0.055/min. Platform voices / Minimax / Fish / Cartesia / OpenAI / Inworld TTS $0.015/min. ElevenLabs Flash $0.040/min (higher ElevenLabs rows on the same table). LLM rows are per-minute (example GPT 4.1 $0.045/min). 20 concurrent included.
• Telephony — US Twilio example $0.015/min; SIP / custom telephony $0. Billing stops the AI fee after transfer; silence still bills because STT stays on.
• Monthly add-ons — Retell phone number $2/mo; extra concurrency $8; knowledge base $8/mo after 10 free; verified number $10/mo.
• Call add-ons — Knowledge Base +$0.005/min; Batch Call +$0.005/dial; Branded Call +$0.10 outbound; Safety Guardrails +$0.005/min; PII Removal +$0.01/min.
• Enterprise — custom (SSO, HIPAA/BAA, dedicated server add-on, 24/7 portal).

You are billed for connected time to the second. Failed connects are free; voicemail bills only while the agent is on the line.

Limitations / costs

• Infra is not the all-in rate. Add LLM + TTS + telephony.
• Hold / silence still bills.
• Free Vapi-style “one number included” is not the model — Retell numbers are $2/mo (custom numbers free).
• Enterprise is the compliance gate (HIPAA / SSO / custom BAA).

Alternatives

• Vapi — Dashboard + $0.05/min hosting and provider pass-through.
• Bland — one $0.14/min Start rate that already includes LLM/STT/TTS.
• ElevenLabs — speech studio if you do not need a phone agent.

Official tutorial

Official Retell AI channel video: How to Build an AI Receptionist That Books Appointments (Tutorial) (oEmbed author: Retell AI).

Written path: Pricing. Official site: retellai.com.

Website

https://www.retellai.com

Source

Catalog row curated for AI Tools Nav. Cover is Retell’s official Create-agent dialog (templates + Generate from prompt). Infra $0.055/min; 20 free concurrent; numbers $2/mo. Tutorial: How to Build an AI Receptionist on @retellai (oEmbed).

Last verified

2026-10-22 (Asia/Shanghai) editorial check.