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Retell AI vs Simple Phones

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. Retell AI starts at $0.07, Simple Phones at $97. Only Retell AI has a free tier. Only Retell AI ships a public API.

Retell AIBuild and run AI phone agents that book, qualify and transfer calls, billed by the minute.Simple PhonesAI voice agent answers business calls around the clock

Side by side

FactRetell AISimple Phones
CategoryVoice Agents & Phone AIVoice Support & Call Centers
Pricing modelFreemiumPaid
Starts at$0.07 minute$97 month
Public APIYesNo
PlatformsWeb, APIWeb
CompanyRetell AI Inc.Simple Phones
Launched20232023
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

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

Simple Phones

Worth a look for a small service business that keeps missing calls and cannot justify a receptionist. At $97 for 100 calls you are buying per call, not per seat, so the math only works if your inbound volume is predictable.

Pros

  • Setup is genuinely quick: forward a number, describe the business, go live
  • Full transcript and log per call, so you can audit what the agent actually said
  • Zapier and webhook output fits alongside an existing CRM instead of replacing it
  • Month-to-month billing with a 14-day trial

Cons

  • Entry price is high next to per-minute voice platforms aimed at builders
  • No publicly documented developer API; integration means webhooks or Zapier
  • Small unfunded team, so roadmap depth and support scale are unproven
  • The site says little about which speech or language models sit underneath

Which one fits

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

Choose Simple Phones if you need

  • Home-service and trades businesses losing after-hours calls
  • Clinics, salons and studios where most calls are booking requests
  • Solo operators replacing a voicemail box with something that converts
  • Testing whether an AI receptionist works before buying a full contact-centre platform

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