ElevenLabs vs Vapi vs Retell AI for phone voice agents

By Robert Breen · Published October 6, 2026 · Prices and features checked as of October 2026

This guide is for office managers, operations leads and owners at law firms, insurance agencies, accounting offices and other white-collar teams thinking about an AI receptionist. Features are as listed on each vendor's own docs as of October 2026. Stepthrough's voice agent lessons are not live yet, so the closest practice today is building the "brain" of an agent, its instructions, memory and tools, in the free AI Social Media Idea Agent lesson.

How do they compare at a glance?

Prices and features as listed on each vendor's own pages, as of October 2026. Plans change often, so check the vendor's pricing page before you buy. Sources are at the end of this page.

What is the difference between ElevenLabs, Vapi and Retell AI?

The biggest difference is where each company started. ElevenLabs began as a text-to-speech and voice cloning company, and its Agents platform (also called ElevenAgents in its docs) builds on that: its overview lists thousands of voices across dozens of languages, a knowledge base for your documents, tools that call your other systems, and a visual workflow builder for multi-step conversations.

Vapi and Retell AI started as voice agent platforms. Vapi describes an agent as three parts you can pick separately: speech-to-text, a language model and a voice, chosen from many providers, including ElevenLabs voices. Retell AI describes itself as a place to build, test, deploy and monitor voice and chat agents with telephony, prompts, tools and analytics built in. In practice that means ElevenLabs leads with the voice, Vapi leads with flexibility, and Retell leads with an all-in-one phone setup.

Which one is easiest if I am not a developer?

All three have a dashboard where you write the agent's instructions, pick a voice and test a call. Vapi's phone quickstart starts from a "Customer Support" template that you edit in the dashboard. Retell offers two styles: a Single Prompt agent, where one set of instructions runs the whole call, and a Conversation Flow agent, where you split the call into steps for tighter control. ElevenLabs has a visual workflow builder for the same kind of step-by-step control.

The harder part for a non-developer is usually the phone line and the connections, not the instructions. Retell lets you buy a US or Canadian number in its own dashboard without a separate phone provider account. Vapi gives one free US number to start. ElevenLabs connects through a Twilio number you import or a SIP trunk, so you may need a Twilio account or help from whoever runs your phone system. Whichever you pick, write and test the agent's instructions in text first; the free AI Email Responder lesson shows how much a clear set of rules changes the output.

What would an AI receptionist for a law firm or insurance agency actually do?

A sensible first job is narrow: answer after hours or when the front desk is busy, greet the caller, collect their name, number and reason for calling, answer a short list of questions you have written answers for (hours, address, what to bring to an appointment), and either book a callback or transfer to a person. Stepthrough's lessons for a made-up agency, Stonebridge Insurance Agency, show why the limits matter: in the free Claim-Status Emails lesson, the reply to a client with an open auto claim must not promise a payment date or a rate decision, because the carrier makes those calls. A voice agent needs the same rules, written into its instructions.

Keep it away from advice. A receptionist agent for a law office should never tell a caller whether they have a case, and one for an accounting office should not answer tax questions. Give it a short list of things it must never say, and a clear escalation rule for when to hand the call to a person.

How does each one hand a call to a real person?

All three can transfer a live call to a phone number. ElevenLabs has a transfer to number tool; its warm transfer messages, where the agent briefs the person who picks up, are available when the number comes in through the native Twilio integration. Vapi's Transfer Call tool supports blind transfers and warm options such as speaking a summary before connecting. Retell's Transfer Call supports cold transfers, warm transfers and an "agentic warm transfer" where a separate agent screens the call with the person before connecting the caller.

Test the handoff before anything else. A caller who asks for a person and gets stuck with the agent is the fastest way to lose trust, so make "transfer me" or "talk to someone" work on every test call.

What compliance information do they publish?

Each vendor publishes its own compliance claims. ElevenLabs' agents trust page says it is SOC 2 Type II, ISO 27001 and PCI DSS Level 1 certified, with HIPAA and GDPR attestations, and its HIPAA docs say a Business Associate Agreement is only available on Enterprise subscriptions. Vapi's trust center lists SOC 2 Type II, SOC 3, HIPAA, PCI DSS, GDPR and CCPA, with the SOC 2 report available under NDA. Retell's compliance docs list HIPAA, SOC 2 Type 1 and Type 2 and GDPR, with a BAA and data processing addendum you can sign yourself.

A vendor's claim is a starting point, not your sign-off. Ask for the SOC 2 report, read the data processing agreement, and check how long call recordings and transcripts are kept. Your own obligations to clients stay with you.

What rules should I follow before an AI answers my phones?

Three habits keep a voice agent honest. First, tell callers they are talking to an AI, in the first line of the greeting. Second, follow call-recording consent rules: they vary by state and country, and some places require every party on the call to agree, so say the call is recorded and check the rules where you and your callers are. Third, always offer a person, through a transfer, a callback or a message.

Outbound calls carry extra rules. The FCC ruled in 2024 that AI-generated voices count as "artificial" voices under the Telephone Consumer Protection Act, so automated outbound calls generally need the person's prior consent. Start with inbound calls, and talk to your lawyer before any outbound campaign. This page is not legal advice.

What does each one cost?

All three bill mainly by usage, so your cost depends on how many minutes your agent talks, which voice and model you choose, and your phone provider. Pricing varies by plan and changes often, so check each official page: ElevenLabs Agents pricing, Vapi pricing and Retell AI pricing. Vapi's page lists model, transcription, voice and telephony costs as separate items, and ElevenLabs and Retell both list an Enterprise option with custom terms. Run a short pilot with real call volumes before you commit.

Who is each one for?

ElevenLabs Agents

For offices that care most about a natural-sounding voice, need several languages, or already use ElevenLabs for voiceovers. Expect to bring a Twilio number or a SIP trunk. A free Stepthrough lesson is coming.

Vapi

For teams with a developer, or a technical office manager, who want to mix and match speech, model and voice providers and build several assistants that hand calls to each other. A free Stepthrough lesson is coming.

Retell AI

For non-developers who want the phone number, step-by-step call flow, transfers and CRM connections in one dashboard, with a self-serve BAA if they need one. A free Stepthrough lesson is coming. Until then, practice the agent's instructions, memory and tools in the free AI Social Media Idea Agent lesson.

Which of these tools have a free Stepthrough lesson?

• ElevenLabs Agents: a free Stepthrough lesson is coming.
• Vapi: a free Stepthrough lesson is coming.
• Retell AI: a free Stepthrough lesson is coming.

Key takeaways

• ElevenLabs started as a voice and text-to-speech company; Vapi and Retell AI are voice agent platforms, and Vapi can even use ElevenLabs voices.
• All three have a no-code dashboard, but phone setup differs: Retell sells US and Canada numbers in its dashboard, Vapi gives one free US number, and ElevenLabs connects through Twilio or a SIP trunk.
• All three can transfer a call to a person; test that handoff before anything else.
• As of October 2026, all three publish compliance claims such as SOC 2 and HIPAA, but check the reports, BAAs and data retention yourself.
• Disclose the AI at the start of every call, follow call-recording consent rules, and always offer a human.

Frequently asked questions

Do I need to code to build an AI receptionist?

Not to start. ElevenLabs, Vapi and Retell AI all let you write instructions, pick a voice and test calls in a dashboard. Connecting a calendar, CRM or your existing phone system is where a developer or your phone provider may need to help.

Can I keep my existing office phone number?

Often, yes, but how depends on the tool and your phone provider. Vapi and Retell support importing numbers and SIP trunking, and ElevenLabs supports imported Twilio numbers and SIP trunks. Ask your phone provider about forwarding or porting before you change anything.

Do I have to tell callers they are talking to an AI?

It is the honest default and Stepthrough recommends it on every call. Disclosure and recording-consent rules vary by state and country, and outbound AI calls fall under the TCPA in the US, so check with your lawyer for your situation.

Is a voice agent safe for client information?

It can be set up carefully, but it depends on the plan and settings. Read each vendor's trust or compliance page, sign the BAA or data processing agreement if you need one, limit what the agent collects, and decide how long recordings are kept.

Where do these prices and features come from?

Every price and feature on this page was checked against the vendor's own page, as of October 2026. No numbers here are estimates or third-party figures. The example businesses in the Stepthrough lessons are made up.

• ElevenLabs docs: Agents platform overview
• ElevenLabs docs: Twilio native integration
• ElevenLabs docs: Transfer to number
• ElevenLabs docs: HIPAA
• ElevenLabs: AI trust and reliability
• ElevenLabs Agents pricing
• Vapi docs: Introduction
• Vapi docs: Phone calls quickstart
• Vapi docs: Transfer Call tool
• Vapi docs: SIP trunking
• Vapi Trust Center
• Vapi pricing
• Retell AI docs: Introduction
• Retell AI docs: Purchase a phone number
• Retell AI docs: Transfer call
• Retell AI docs: Compliance
• Retell AI pricing
• FCC: AI-generated voices in robocalls