# 10 best AI voice agents for phone support in 2026

By Samuel Oram-Jones

The best AI voice agents for phone support in 2026 are Bland, Vapi, PolyAI, Sierra, Synthflow, Cognigy, Parloa, Thoughtly, Voiceflow, and Retell, and Bland ranks first for enterprise support lines because it is full stack. This ranking compares each AI voice agent on who builds the AI, where calls can run, and what a minute costs, as of November 2026.

## What are the best AI voice agents for phone support?

The best AI voice agent for phone support overall is Bland, because one company builds and runs every AI model on a support call, and the other nine each lean on outside companies for at least one of them.

- **Bland:** Best overall for enterprise support lines
- **Vapi:** Best for developers assembling their own voice stack
- **PolyAI:** Best for enterprises that want a managed, quoted agent
- **Sierra:** Best for enterprise teams buying outcome-priced agents
- **Synthflow:** Best for sales-led, multi-channel voice teams
- **Cognigy:** Best for contact centers with their own platform team
- **Parloa:** Best for enterprise teams buying quoted voice and chat
- **Thoughtly:** Best for inbound lead conversion across voice and text
- **Voiceflow:** Best for CX teams building agents on a visual builder
- **Retell:** Best for developer teams that pick their own model and voice

| Provider | Best for | Price | Who builds the AI | iMessage |
|---|---|---|---|---|
| Bland | Enterprise support lines | $0.14 per minute on self-serve Start, $0.12 on self-serve Build plus $299 a month, phone billed separately | Bland builds all of it | Native on Enterprise |
| Vapi | Developers assembling a stack | $0.05 per minute for hosting, plus providers | Other companies | No |
| PolyAI | Managed, quoted agents | Quote only | Mixed | No |
| Sierra | Outcome-priced agents | Outcome-based, no published rate | Mixed | Business Chat |
| Synthflow | Sales-led annual contracts | Annual agreement only | Mixed | No |
| Cognigy | Contact centers with a platform team | Quote only | Other companies | No |
| Parloa | Quoted voice and chat | Quote only | Mixed | No |
| Thoughtly | Inbound lead conversion | Quote only | Mixed | Via partner |
| Voiceflow | Visual agent builder | Request pricing | Mixed | No |
| Retell | Developer teams | $0.07 to $0.31 per minute, with the model and voice as separate lines | Other companies | No |

## What should buyers check in AI voice agents for phone support?

A support team should check who builds each model on a call, because price, security review, and how a caller hears the agent all depend on how many companies sit behind it.

Vapi, Cognigy, and Retell take their language model from other companies, PolyAI, Sierra, Synthflow, Parloa, Thoughtly, and Voiceflow mix their own models with outside ones, and Bland builds its language, speech, and transcription models itself. Each outside company is one more name in a [security review](/blog/call-center-security-best-practices), and a headline rate rarely includes all of them.

![Bland's trust page, which reads Pass security review on day one, with voice, text to speech, transcription, and language models all owned and operated by Bland.](/images/compare/bland-trust.jpg)

Support lines also carry the most sensitive data a company handles, so where a call runs matters. Enterprise customers get dedicated orchestration and dedicated GPUs run by Bland.

Compliance paperwork comes next, and a BAA is the contract [HIPAA](/hipaa-compliant-voice-ai) requires before a vendor handles patient information, and card payments need a clear [PCI DSS](/pci-compliant-voice-ai) statement for any line that takes a payment.

All ten providers here hold SOC 2 or a SOC 2 report, Bland self-attests to PCI DSS v4.0.1 and shares its attestation under NDA on Enterprise, and Bland holds FedRAMP 20x Class A, a level of the US government's cloud security program. Sierra holds FedRAMP High through Knox Systems rather than its own authorization, and Retell bars card data unless it agrees in writing.

A support line that also texts customers should be checked for messaging. Bland runs branded iMessage agents natively on Enterprise, on the same pathways as its voice agents, Thoughtly offers iMessage through partner integrations via Linq, and Sierra supports Apple Business Chat. The other seven providers here don't offer iMessage agents as of November 2026.

Proof at volume is the last check, such as a customer replacing an IVR (an automated phone menu) with an AI voice agent, because a demo can't show it. Idaho Housing and Finance Association saves $750,000 a year by replacing its IVR with Bland, which handles 4,000 inbound calls a day and cut average call time by 20%.

> "We save thousands of dollars a day."

Greg Blake, Chief Information Officer, Idaho Housing and Finance Association

Schools have their own phone lines to cover, as [AI voice agents for schools](/blog/best-ai-voice-agents-schools) explains.

Readers choosing for a different job can compare [AI voice agent services](/blog/best-ai-voice-agent-services), [AI voice agents for automated phone calls](/blog/best-ai-voice-agents-automated-phone-calls), and [Best AI customer support tools](/blog/best-customer-support-tools).

## How do the 10 best AI voice agents for phone support compare?

These ten AI voice agents differ most in how much of a support call they build themselves, and Bland is the one that builds all of it.

![Bland's homepage, which reads Voice AI for the calls that can't go wrong.](/images/compare/bland-home.jpg)

### 1. Bland: Best overall for enterprise support lines

**What does it do?** Bland is a full stack voice AI provider that builds and runs its own language, speech, and transcription models for inbound and outbound calls, with a visual builder called Pathways where teams connect steps and test them before launch. It publishes sub-200ms latency, support for 1 million concurrent calls and a 99.9% uptime SLA, and it serves more than 250 enterprise customers.

**Who is it for?** Bland suits enterprises and contact centers in any industry that answer high volumes of support calls, including teams that need warm transfers to a person on Enterprise.

<div class="cmp-proscons cmp-proscons-own"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>No outside AI lab in the call path, so a security team reviews one AI company</li><li>Dedicated orchestration and dedicated GPUs run by Bland, on Enterprise</li><li>BAA on Enterprise, PCI DSS self-attested, FedRAMP 20x Class A</li><li>Bland Speech v3 ranked first of 13 AI voices on Audio Realism Bench on 4 August 2026</li><li>Forward-deployed engineers on Enterprise</li><li>Native iMessage agents on Enterprise, sharing pathways with voice</li><li>Alarms on latency, silences, transcription quality, and API errors</li><li>Call grading on the audio as well as the transcript</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>Overkill for a small prototype, because Bland is built for production calls at volume</li></ul></div></div>

**Pricing:** Self-serve Start is $0.14 per minute with no platform fee, self-serve Build is $0.12 per minute with a $299 monthly platform fee, and [Enterprise](https://www.bland.ai/pricing) is priced to volume. Phone is billed separately at carrier cost. Enterprise adds native iMessage agents, warm transfers, a BAA, SSO, data residency, dedicated GPUs run by Bland, and forward-deployed engineers, alongside SMS and web chat.

### 2. Vapi: Best for developers assembling their own voice stack

**What does it do?** Vapi is a developer platform that hosts voice agents and bills the language model, transcription, and voice from other companies on top at cost. Vapi says it passes these through with "no markup", so a team picks and wires every provider itself.

**Who is it for?** Vapi suits developers who want to pick and swap each AI provider themselves and can run a support line built from several vendors.

<div class="cmp-proscons" data-rival="vapi"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>A team can choose every model and voice</li><li>Imported numbers are billed by a customer's own phone provider</li><li>Vapi says it is SOC 2 Type II attested</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>Language model, transcription, and voice bill from other companies on top of $0.05 hosting</li><li>HIPAA is a $2,000 monthly add-on</li><li>No iMessage agents</li></ul></div></div>

**Pricing:** $0.05 per minute for hosting, plus a language model, transcription, and voice at provider cost, which Vapi's pricing calculator puts at up to $0.0452, $0.0099, and $0.0238 a minute, before phone.

### 3. PolyAI: Best for enterprises that want a managed, quoted agent

**What does it do?** PolyAI builds and runs a voice agent for a customer on quoted per-minute pricing, with its own Raven model family beside GPT and Claude models. PolyAI also sells a Dialog-RSN-1 model API at 2¢ per connected minute, without telephony or orchestration.

**Who is it for?** PolyAI suits large consumer-facing companies that want it to build and run their support agent for them.

<div class="cmp-proscons" data-rival="polyai"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>PolyAI handles the build and the ongoing running</li><li>Has SOC 2 Type II and ISO/IEC 27001</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>No public rate for a managed agent</li><li>Its contract says "the total handle time is rounded up to the next 30-second increment"</li><li>No iMessage agents</li></ul></div></div>

**Pricing:** A managed agent is quoted per minute with no public rate.

### 4. Sierra: Best for enterprise teams buying outcome-priced agents

**What does it do?** Sierra started as a chat-first platform for customer support, added voice later, and covers chat, voice, email, SMS, and WhatsApp. Sierra says it is "combining frontier, open-weight, and proprietary models" and that it "automatically switches between LLM providers to optimize your agent".

**Who is it for?** Sierra suits enterprise customer experience teams that want a managed agent and are happy to negotiate pricing.

<div class="cmp-proscons" data-rival="sierra"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>Sierra says it "holds PCI DSS Level 1 Service Provider certification"</li><li>Has SOC 2, HIPAA, GDPR, PCI, and ISO 27001, and holds FedRAMP High through Knox Systems rather than its own authorization</li><li>SMS and WhatsApp beside voice and chat</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>No published rate</li><li>No self-serve mode</li><li>Routes each call across outside language model providers, so a security review covers more than one AI company</li></ul></div></div>

**Pricing:** Sierra says "With outcome-based pricing, Sierra gets paid only when we complete a task for you." Sierra prices routing or greeter-style interactions on consumption, and publishes no rate.

### 5. Synthflow: Best for sales-led, multi-channel voice teams

**What does it do?** Synthflow sells voice agents through one annual enterprise agreement that scopes in telephony, integrations, and launch support, and it offers WhatsApp and SMS chat beside voice. Synthflow says it is built on "proprietary orchestration and models from OpenAI, ElevenLabs, Deepgram, and custom in-house logic".

**Who is it for?** Synthflow suits mid-market and enterprise teams that want a sales-scoped platform and are happy to sign an annual agreement before they launch.

<div class="cmp-proscons" data-rival="synthflow"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>Has SOC 2 Type 2, ISO/IEC 27001, HIPAA, and GDPR coverage</li><li>Forward-deployed engineers launch agents with a customer's team where the agreement includes launch support</li><li>WhatsApp and SMS chat channels</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>Annual enterprise agreement only, with no free plan or trial and no rate by the minute</li><li>No iMessage agents</li></ul></div></div>

**Pricing:** Annual agreement only, with no public per-minute rate, and purchased phone numbers cost $1.50 a month.

### 6. Cognigy: Best for contact centers with their own platform team

**What does it do?** Cognigy sells a conversational AI platform that connects to language, speech, and transcription providers a customer chooses, and it publishes no rate. Cognigy says it supports "LLM integration with top providers such as OpenAI, Azure, Anthropic, Amazon Bedrock, Google, and Mistral AI", and its Voice Gateway connects an agent to the phone network over SIP, the standard internet-calling connection.

**Who is it for?** Cognigy suits large contact centers with a platform team that want to wire together their own model and speech vendors.

<div class="cmp-proscons" data-rival="cognigy"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>Voice Gateway connects over SIP, with Twilio endpoints for SMS, and WhatsApp</li><li>Cognigy holds SOC 2 Type II, ISO 27001, and PCI DSS</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>A customer brings API credentials for each language model it connects</li><li>Pricing runs through a demo request</li><li>No iMessage agents</li></ul></div></div>

**Pricing:** Quote only, after a demo request.

### 7. Parloa: Best for enterprise teams buying quoted voice and chat

**What does it do?** Parloa sells an AI agent management platform for enterprise customer service across voice and chat. Parloa says it uses "consumption-based pricing: per minute for voice and per interaction for chat", and its agents run on language models from OpenAI, Anthropic, Google, and others.

**Who is it for?** Parloa suits large service organizations in regulated industries that buy by quote and are comfortable with a mix of model providers.

<div class="cmp-proscons" data-rival="parloa"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>Has ISO 27001, SOC 2 Type 1 and 2, PCI DSS, HIPAA, DORA, GDPR, and the EU AI Act</li><li>Parloa says agents converse in "over 140 languages & variants"</li><li>Offers a Business Associate Agreement</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>No published rate</li><li>Parloa says "ElevenLabs must be accepted as a subprocessor before enabling EU processing"</li><li>No iMessage agents</li></ul></div></div>

**Pricing:** Parloa says "Rates reflect the complexity of each use case", and publishes no rate.

### 8. Thoughtly: Best for inbound lead conversion across voice and text

**What does it do?** Thoughtly sells agents that call, text, and email inbound leads, qualify them, book meetings, and write back to a CRM. Thoughtly describes its product as "inbound lead conversion, not cold outbound and not an AI SDR", and a customer picks a GPT, Claude, or Gemini language model with stock voices from a Cartesia and ElevenLabs catalog.

**Who is it for?** Thoughtly suits revenue teams in mortgage, insurance, real estate, and similar fields that get 500+ opted-in inbound leads a month.

<div class="cmp-proscons" data-rival="thoughtly"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>Has a 99.9% uptime SLA on its Scale plan</li><li>Has 200+ integrations</li><li>Books meetings and writes back to a CRM</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>No public rate, because Flex, Scale, and Enterprise all route to sales</li><li>A customer's language model is a GPT, Claude, or Gemini model, and stock voices come from Cartesia and ElevenLabs</li></ul></div></div>

**Pricing:** No public rate. Flex, Scale, and Enterprise are sold through sales, with 10 concurrent calls on Flex and 100+ on Scale.

### 9. Voiceflow: Best for CX teams building agents on a visual builder

**What does it do?** Voiceflow is a platform for building, testing and deploying chat and phone agents with playbooks and workflows. Voiceflow says "Connect a phone number to your agent for inbound calls, outbound calls, and SMS" and offers a choice of language models: "Choose from the biggest LLM providers, or bring your own model."

**Who is it for?** Voiceflow suits customer experience teams and agencies that design agents in a visual studio and pick their own models.

<div class="cmp-proscons" data-rival="voiceflow"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>Free trial, no credit card required</li><li>Has SOC 2 Type II, ISO 27001, GDPR, and HIPAA</li><li>Voiceflow says it does not use customer data to train any machine learning or AI models</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>Usage bills in credits that depend on the vendor and model, so a minute has no single price</li><li>No iMessage agents</li></ul></div></div>

**Pricing:** Voiceflow says "Every interaction, from chat messages to LLM calls to voice minutes, consumes a certain number of credits depending on the vendor and model you use." Its credits table lists minutes on phone calls at $0.05, and enterprise pricing goes through a "Request pricing" route.

### 10. Retell: Best for developer teams that pick their own model and voice

**What does it do?** Retell is a platform for building and monitoring AI voice and chat agents, billed per minute with the language model and voice priced as separate lines. A customer's own SIP trunk (a connection to the phone network) carries no Retell phone charge, and phone on Twilio or Telnyx is billed on top.

**Who is it for?** Retell suits developer-led teams that want to choose their own language model and voice and pay per minute.

<div class="cmp-proscons" data-rival="retell"><div class="cmp-proscons-pros"><p><strong>Pros</strong></p><ul><li>A wide choice of language models and voices</li><li>Has SOC 2, HIPAA, and GDPR coverage</li></ul></div><div class="cmp-proscons-cons"><p><strong>Cons</strong></p><ul><li>Advertises "We guarantee >99.9% uptime", while its terms say "at least 99.5% uptime"</li><li>PII (personal data) Removal adds $0.01 a minute</li><li>No iMessage agents</li></ul></div></div>

**Pricing:** $0.07 to $0.31 per minute depending on the language model and voice, with Retell Voice Infra, GPT-4.1, and an ElevenLabs Flash voice coming to $0.14 per minute before phone.

### How were these AI voice agents ranked?

Providers were compared on who builds the AI, where calls can run, price per minute before phone, compliance, and voice realism, with weight on what enterprise support calls need. Every claim about a provider comes from its own public pages as read in November 2026, and voice scores come from Design Arena's chart of 4 August 2026.

Closer comparisons sit in [Bland vs Vapi](/compare/bland-vs-vapi), [Bland vs PolyAI](/compare/bland-vs-polyai), [Bland vs Sierra](/compare/bland-vs-sierra), [Bland vs Synthflow](/compare/bland-vs-synthflow), [Bland vs Cognigy](/compare/bland-vs-cognigy), [Bland vs Parloa](/compare/bland-vs-parloa), and [Bland vs Retell](/compare/bland-vs-retell).

## How much do AI voice agents for phone support cost?

Enterprise pricing is custom, set with Bland's sales team. AI voice agents for phone support charge per minute or by quote, and what a minute includes differs, so each price below states its basis. Bland's self-serve Start plan is $0.14 per minute for its language model, transcription, and speech together, and Bland replaced an earlier flat $0.09 rate with Start and Build in December 2025.

![Bland's pricing page, with self-serve Start at $0.14 a minute, self-serve Build at $0.12 a minute, and custom Enterprise pricing.](/images/compare/bland-pricing.jpg)

Every total below is AI before phone, with Vapi at its calculator defaults. Retell's card adds Retell Voice Infra, GPT-4.1, and an ElevenLabs Flash voice to reach $0.14 per minute, while Retell publishes a range of $0.07 to $0.31 per minute depending on the model and voice.

Vapi's card adds hosting to the top of each range Vapi says its providers run, and phone is billed by whichever provider a customer connects. PolyAI, Sierra, Synthflow, Cognigy, Parloa, Thoughtly, and Voiceflow publish no per-minute rate for a managed agent, so no bill can be added up for them.

| Vendor | What a minute pays for | Total per minute | Phone |
|---|---|---|---|
| Bland Start (self-serve) | All AI: model, transcription, speech $0.14 | $0.14 before phone | Billed separately at carrier cost |
| Retell | Voice infrastructure $0.055, GPT-4.1 $0.045, ElevenLabs Flash voice $0.04 | $0.14 before phone | Twilio at $0.015 a minute, billed on top |
| Vapi | Hosting $0.05, Transcription $0.0099, Language model $0.0452, Voice $0.0238 | $0.1289 before phone | Free on Vapi numbers, billed on top on Twilio at up to $0.014 a minute |

Bland Start (self-serve): Self-serve Start has no platform fee. Self-serve Build is $0.12 a minute plus $299 a month. Phone and transfers bill separately. Retell: Retell Voice Infra, GPT-4.1, and an ElevenLabs Flash voice, before Twilio phone minutes. Vapi: Hosting plus the top of each range on Vapi's pricing calculator, before phone.

## Which AI voice agent sounds most like a real person?

Bland Speech v3 ranked 1st of 13 AI voices on Design Arena's Audio Realism Bench on 4 August 2026, at 1365, and every outside voice in those results that the other providers here let a customer choose scored lower.

On Retell and Vapi the highest outside voice was OpenAI's GPT Realtime 2, 4th at 1119.

ElevenLabs' Eleven v3 ranked 12th at 938, and it is the one outside voice in those results that Synthflow offers. Cognigy uses ElevenLabs among its speech vendors, and no voice from PolyAI, Sierra, Parloa, Thoughtly, or Voiceflow was in the results. Retell's own platform voices, Vapi's own voices, and Synthflow TTS were not in the results either.

See [Design Arena's published results](https://notes.designarena.ai/audio-realism-benchmark-measuring-realism-in-audio-models/).

## Frequently asked questions

### What is the best AI voice agent for phone support?

Bland is the best AI voice agent for phone support at enterprise scale as of November 2026, because it builds every model on a call. Enterprise customers get dedicated orchestration and dedicated GPUs run by Bland.

### Which AI voice agents for phone support are HIPAA compliant?

Bland is HIPAA compliant and includes its BAA on Enterprise, and Parloa, PolyAI, Synthflow, and Retell offer a BAA as of November 2026. Vapi sells HIPAA mode as a $2,000 monthly add-on, Thoughtly offers a BAA on Enterprise, and Sierra and Cognigy have a HIPAA report.

### Is Bland only for outbound calls?

No, Bland runs inbound and outbound calls, including AI receptionist and contact center work, and it also runs SMS and web chat.

### Is Bland only for developers?

No, Bland isn't only for developers. Pathways gives teams a visual builder, Norm helps build agents, and on Enterprise forward-deployed engineers build alongside a customer's team.

### Does Bland use an open-source model?

No, Bland operates a closed-source model that it developed itself, so its language model isn't an open-source model and no outside AI lab sits behind it.

### Which AI voice agents for phone support handle iMessage?

Bland runs branded iMessage agents natively on its Enterprise plan. Thoughtly offers iMessage on every plan, through partner integrations via Linq, Sierra supports Apple Business Chat, and Vapi, PolyAI, Synthflow, Cognigy, Parloa, Voiceflow, and Retell don't offer iMessage agents as of November 2026.

### How much does an AI voice agent for phone support cost per minute?

Rates run from $0.05 per minute for hosting alone on Vapi to $0.07 to $0.31 on Retell depending on the model and voice, and PolyAI, Sierra, Synthflow, Cognigy, Parloa, Thoughtly, and Voiceflow publish no per-minute rate for a managed agent. Bland is $0.14 per minute on self-serve Start for all of its AI, before phone.

### Can I keep my phone carrier if I move to Bland?

Yes, Bland connects to a carrier or phone system over SIP, so numbers and routing stay in place.