Vapi or Retell AI — which voice agent platform should I build on?
TL;DR
Vapi is the more flexible, developer-first orchestration layer with the broadest model/voice marketplace, starting around $0.05/min base (real-world blended cost $0.08–0.15/min). Retell AI offers a comparable pay-as-you-go range ($0.07–0.31/min, realistic $0.11–0.15/min) with a more opinionated, faster-to-ship builder and a dedicated $8,000+ Enterprise tier for fully managed deployments.
What’s in this guide
01 Vapi vs Retell AI at a glance
Both are voice-agent orchestration layers — they stitch together telephony, speech-to-text, an LLM, and text-to-speech into a single low-latency call pipeline, so you’re not integrating four separate vendors yourself. The difference is philosophy: Vapi leans maximally flexible (bring almost any model/voice/telephony combination), Retell leans toward a faster, more opinionated path to a production agent.
| Vapi | Retell AI | |
|---|---|---|
| Base rate | $0.05/min orchestration | $0.07–0.31/min (voice engine dependent) |
| Realistic all-in cost | $0.08–0.15/min | $0.11–0.15/min |
| Model/voice flexibility | Very high — broad marketplace | High, more curated defaults |
| Free credits | Self-serve trial credits | $10 free (~67–90 min at realistic rates) |
| Enterprise tier | Custom volume pricing | Starts at $8,000, white-glove onboarding |
| Best for | Teams that want full control of the stack | Teams that want to ship fast with less config |
02 Real per-minute cost breakdown
Neither platform’s advertised headline rate is what you’ll actually pay — both are orchestration-only fees on top of which you stack transcription, the LLM, and text-to-speech.
Vapi: hosting ~$0.05/min + transcription (Deepgram-class) ~$0.01/min + LLM ~$0.02–0.20/min depending on model + TTS (ElevenLabs-class) ~$0.04/min + Twilio telephony ~$0.013/min per leg. A typical GPT-4o + Deepgram Nova-2 + ElevenLabs standard build lands around $0.08–0.15/min total.
Retell AI: voice infra + standard TTS gets you to about $0.07/min; stack an LLM ($0.003–0.08/min) and telephony ($0.015/min) and the realistic floor is $0.085–0.19/min, with most production deployments landing at $0.11–0.15/min.
03 Where each platform actually wins
- Vapi wins on flexibility: broadest marketplace of LLMs, voice engines, and telephony providers — the right call if you need a specific model/voice combination or plan to swap providers as pricing/quality shifts.
- Retell wins on speed-to-production: more opinionated defaults and a builder aimed at getting a working agent live faster, with less infrastructure decision-making up front.
- Retell wins on managed enterprise support: the $8,000+ Enterprise tier is a real option for teams that want a vendor-managed deployment rather than an in-house build.
- Vapi wins on cost ceiling control: because you choose every component, it’s easier to deliberately cap spend by picking cheaper model/voice tiers when volume gets large.
The platforms are converging on price — the real decision is whether your team wants to own the stack (Vapi) or rent a faster path to production (Retell).
04 Which one to build on
If you have engineering capacity and want maximum control over cost and quality tradeoffs long-term, Vapi’s flexibility pays off. If you want a production voice agent live in days with fewer infrastructure decisions — or you want the option to hand the whole thing to a managed Enterprise team later — Retell AI is the faster path.
Most SMBs working with Growth100X skip this decision entirely: we build and host the voice agent on whichever backend fits the use case, so you get a working AI receptionist without evaluating orchestration platforms yourself.
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FAQ Frequently Asked Questions
Is Vapi or Retell AI cheaper?
Their realistic all-in per-minute costs overlap heavily ($0.08–0.15/min for Vapi vs $0.11–0.15/min for Retell) — neither is dramatically cheaper once you account for the full LLM/TTS/telephony stack, not just the advertised base rate.
Can I switch from Vapi to Retell AI (or vice versa) later?
Yes, but expect real migration work — call flows, prompts, and integrations are platform-specific, so switching later means rebuilding rather than a simple config export.
Do I need engineering resources to use either platform?
Both are developer-first tools built around APIs and configuration, so some technical setup is expected — most small businesses use an agency or freelance builder rather than building the agent themselves.
What’s the minimum realistic monthly cost for a small business AI voice agent?
At $0.10–0.15/min realistic cost and typical SMB call volumes (a few hundred minutes/month), raw usage costs often land in the $30–150/month range — before any build, hosting, or management fee on top.
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