Retell AI vs Vapi: which to build an AI receptionist on

Retell AI and Vapi are two of the best-known platforms for building AI phone agents. Neither is a receptionist you switch on: on both, you write the agent’s instructions, choose its AI model and voice, connect a phone number and the tools it uses, and pay by the minute (Retell docs, Vapi docs). So the real question for a business owner is which one is less work to turn into a dependable receptionist, and which costs less to run.

Short answer: Retell AI for most businesses building a receptionist, especially medical and dental offices. Vapi for developers who want to pick every provider and wire up their own tools.

Cost at 200 calls a month

Both charge a platform fee per minute and pass through the cost of the AI model, voice and phone line you choose.

• Retell AI: $0.055 a minute, billed per second, plus the rest. Retell puts the all-in cost at $0.07 to $0.31 a minute (Retell pricing).
• Vapi: $0.05 a minute for hosting, plus the rest at provider cost. Vapi’s own calculator puts 1,000 minutes at $82 to $129, or $0.08 to $0.13 a minute (Vapi pricing).

For 200 calls of about 3 minutes, so 600 minutes, usage comes to about $42 to $186 on Retell and $49 to $77 on Vapi. The wider Retell range reflects a wider menu of models, from very cheap to premium, not a higher base price. Vapi’s range is narrower because its calculator assumes a few specific providers.

The extras differ more than the rates:

	Retell AI	Vapi
Phone number	$2 a month each	1 free US number (inbound only)
Texting callers	$20 a month plus $0.01 a text	Through your own Twilio account
Concurrent calls included	20	4 without a package (10 on the $29 Core package)
Free credit to start	$10	$5
HIPAA	BAA available, no add-on fee	$2,000 a month add-on

A realistic receptionist with texting comes to about $65 to $210 a month on Retell and roughly $50 to $110 on Vapi, before any developer time. Vapi is often cheaper on the bill; Retell is often cheaper on the build.

Setting it up

This is where they differ most for a business owner.

Retell has an Auto Receptionist path: four self-serve steps that start from your website. Retell says a standard setup needs no engineering team and most front desks go live in a few days (Retell Auto Receptionist). You can also build visually with a drag-and-drop conversation flow, or hire Retell’s implementation team or a certified partner.

Vapi’s dashboard gets a first agent talking in about five minutes from templates such as Customer Support and Appointment Scheduler, and gives you a free US number to test with (Vapi phone quickstart). Beyond that, it’s built for developers: an API, SDKs, a CLI, configuration as code, simulations and monitoring. That depth is why agencies and engineering teams like it.

Booking, transfers and integrations

Both agents can transfer calls, book appointments, record calls and summarize them, and make outbound calls.

Retell connects to more of what a small business already uses. It books into Cal.com, Calendly, GoHighLevel, Google Calendar and Squarespace Scheduling, and lists integrations with HubSpot, Salesforce, Zoho CRM, Jobber, QuickBooks, Zapier, Make and n8n (Retell integrations).

Vapi has ready-made tools for Google Calendar and GoHighLevel (Vapi Google Calendar tool), plus blind and warm transfers. Anything else, such as field-service software, means custom work through its API.

Retell documents support for 55 languages, depending on the voice and speech providers you choose (Retell language support).

Health information

If you’re a medical, dental or therapy practice, this settles it. Retell offers a HIPAA BAA without an extra platform fee (Retell compliance). Vapi’s HIPAA mode costs $2,000 a month and can’t be combined with its zero data retention option (Vapi HIPAA). At 200 calls a month, that add-on is many times the cost of the calls.

Verdict

Choose Retell AI if you’re a business owner or a small agency building one receptionist, if you need it booking into Calendly or a CRM without custom code, or if you handle health information. Its Auto Receptionist setup is the shortest path from signup to answered calls on either platform.

Choose Vapi if you have a developer, want to choose and swap every model, voice and transcriber, need deep custom logic, or are building many agents as code. Its usage range is narrower and its low end is close to Retell’s.

If neither sounds like something you want to maintain, a ready-made receptionist costs in the same range at this volume: Rosie covers 1,000 minutes for $149 a month and Upfirst 300 calls for $159.95, with nothing to build. See Vapi alternatives for both kinds of option, our Retell AI review and Vapi review, or AI voice agent vs AI receptionist.