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Bolna 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. Bolna starts at $0.06, Retell AI at $0.07. Only Retell AI has a free tier. Both ship a public API.

BolnaPhone agents for inbound and outbound calls, with 10+ Indian languages and your pick of ASR, LLM and TTSRetell AIBuild and run AI phone agents that book, qualify and transfer calls, billed by the minute.

Side by side

FactBolnaRetell AI
CategoryVoice Agents & Phone AIVoice Agents & Phone AI
Pricing modelPaidFreemium
Starts at$0.06 minute$0.07 minute
Public APIYesYes
PlatformsWeb, APIWeb, API
CompanyWhismurwave Inc.Retell AI Inc.
Launched—2023
Last verifiedSep 6, 2026Sep 6, 2026

What our research says

Bolna

Bolna competes on two things Western voice-agent platforms handle badly: Indian language coverage and per-minute price. Being able to swap the recognition, language and speech models independently is genuinely useful when one vendor's accent handling fails on your callers. It is a developer product first — the playground exists, but the APIs and telephony wiring are where the work is.

Pros

  • Over ten Indian languages plus English, an area most voice platforms cover poorly
  • Twenty-plus interchangeable ASR, LLM and TTS models rather than a single fixed stack
  • APIs for agents, calls, numbers, knowledge bases and batch dialling, plus n8n, Make and Zapier
  • 6 cents a minute billed in 30-second increments, with volume rates down to about 4.5 cents

Cons

  • Purely metered, so a bad prompt loop turns directly into spend
  • Telephony charges from Twilio, Plivo or Vobiz are additional and not included in the quoted rate
  • Pay-as-you-go requires a credit purchase of at least $10 up front
  • Concurrency and support levels are tied to the Pilots or Enterprise commitments

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 Bolna if you need

  • Teams running call operations in Hindi, Tamil, Telugu or other Indian languages
  • Developers who want to choose their own ASR, LLM and TTS combination per agent
  • High-volume outbound campaigns where a per-minute rate under 6 cents matters

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 Bolna alternatives →Browse all Voice Agents & Phone AI →