AI voice agents handle phone calls autonomously using speech-to-text, an LLM, and text-to-speech. For developer teams building production call infrastructure, Vapi is the most flexible platform, while Retell AI offers a cleaner balance of developer control and lower-code usability. Bland AI suits high-volume outbound campaigns and Phonely is the fastest path to a live answering agent for a small business. The single most important thing to evaluate is real-call latency and reliability, not how the demo sounds.
Seven platforms tested on latency, voice naturalness, telephony depth, and what you actually pay per minute
AI voice agents are not glorified IVR trees. They listen, reason, and respond in real time, handling inbound support calls, outbound appointment reminders, and sales qualification without a human on the line. Toolradar data: 328 of the 773 AI agent tools we track run on a freemium model, letting you test a voice agent before you pay.
The hard part is not generating a convincing voice. Text-to-speech is now a commodity. The hard part is keeping end-to-end latency below 800 milliseconds on a real PSTN call, recovering gracefully when the caller interrupts, and staying on-task across a noisy 3-minute conversation.
This guide covers seven platforms across the developer-API and no-code spectrum: where each excels, where it struggles, and what the true per-minute cost looks like once you add telephony and LLM charges.
Top Picks
Picked by editorial review, informed by G2 and Capterra review volume and rating and by media mentions, the signals behind our category rankings. How we rate
The most flexible developer platform for building production-grade voice AI pipelines
Starting price
Free plan
Best for
Engineering teams who need full control over LLM, TTS, and telephony provider choices
Low-latency voice agent platform balancing developer API depth with a usable visual builder
Starting price
Free plan
4.5 (2,640 reviews)
Best for
Teams who want production reliability and a visual flow builder without giving up API access
Outbound-focused voice agent platform built for high-volume calling campaigns
Starting price
Custom
Best for
Sales and operations teams running large-scale outbound call campaigns
| Tool | Starting price | Rating | Best for |
|---|---|---|---|
| Vapi | Free plan | n/a | Engineering teams who need full control over LLM, TTS, and telephony provider choices |
| Retell AI | Free plan | 4.5 2,640 reviews | Teams who want production reliability and a visual flow builder without giving up API access |
| Bland AI | Custom | n/a | Sales and operations teams running large-scale outbound call campaigns |
| ElevenLabs | From $5/mo | 4.6 1,236 reviews | Teams for whom voice quality and emotional naturalness are the primary requirement |
| Cartesia | From $5/mo | n/a | Developer teams building real-time voice agents on the underlying speech models rather than a full orchestration platform |
| Vocode | Free plan | n/a | Engineering teams who want to self-host, audit the full stack, or embed voice AI directly into their product |
| Phonely | From $50/mo | n/a | Small and mid-size businesses that need a 24/7 AI receptionist without developer resources |
- Starting price
- Free plan
- Free plan
- Yes
Best for: Engineering teams who need full control over LLM, TTS, and telephony provider choices
- Pro: Bring-your-own-provider architecture works with OpenAI, Anthropic, ElevenLabs, and dozens of others
- Pro: Flow Studio visual builder added for simpler conversation design without losing API depth
- Pro: Active developer community and detailed documentation with code examples
- Con: True per-minute cost is well above the $0.05 base rate once LLM and TTS are added; budget carefully
- Con: HIPAA BAA is available but carries an additional monthly fee, which is steep for early-stage teams
Retell AI
Low-latency voice agent platform balancing developer API depth with a usable visual builder
- 4.8 on G2 (2,639 reviews)
- 0.5 on SourceForge (1 reviews)
- Starting price
- Free plan
- Free plan
- Yes
- Rating
- 4.5 (2,640 reviews)
Best for: Teams who want production reliability and a visual flow builder without giving up API access
- Pro: Claims end-to-end latency as low as 600ms, which is among the lowest stated figures in the category
- Pro: 20 concurrent calls included by default, with incremental overage pricing that scales reasonably
- Pro: SOC 2 certified and HIPAA-ready with SSO, making it viable for regulated industries
- Con: Advertised $0.07/min covers only the voice engine; realistic all-in cost runs $0.11 to $0.19/min
- Con: Less provider flexibility than Vapi for teams with strong opinions about which LLM to use
The lack of a flat monthly plan may surprise heavy users, but the free tier and enterprise custom pricing offer flexibility.
- Starting price
- Custom
- Free plan
- No
Best for: Sales and operations teams running large-scale outbound call campaigns
- Pro: Pathways visual builder makes it practical to design branching conversation flows without deep coding
- Pro: Strong outbound calling toolset with SMS, call transfers, and CRM integrations built in
- Pro: Supports voice cloning and multilingual transcription for localized campaigns
- Con: Pricing shifted to subscription tiers starting at $299/month; usage fees are additional on top
- Con: Voice cloning and multilingual transcription carry extra fees that can push costs up significantly
ElevenLabs
TTS market leader that extended into conversational voice agents with standout voice expressiveness
- Starting price
- From $5/mo
- Free plan
- Yes
- Rating
- 4.6 (1,236 reviews)
Best for: Teams for whom voice quality and emotional naturalness are the primary requirement
- Pro: Expressive Mode produces genuinely natural speech including tone shifts, pauses, and emotional cues across 70+ languages
- Pro: Voice cloning quality is among the best available, important for brand-consistent agents
- Pro: Agents pricing at $0.08 to $0.12/min is transparent and per-minute, not per-character like the base TTS
- Con: Agent orchestration depth (tool calling, telephony management) is less mature than Vapi or Retell
- Con: Base plan character quotas and agent minutes are separate billing systems, which complicates cost modeling
The main gotcha: credit consumption varies by model, Flash/Turbo models cost 0.5 credits per character, but the flagship Multilingual v2 costs 1:1, so your effective minutes depend heavily on which voice model you use.
Watch out
Credit consumption varies by model: Multilingual v2 uses 1 credit per character, but Flash/Turbo models use only 0.5 credits per character. Choosing the right model can double your effective quota.
Cartesia
Low-latency speech API and managed voice agents, ranked #1 on Artificial Analysis' Speech Arena leaderboard
- Starting price
- From $5/mo
- Free plan
- Yes
Best for: Developer teams building real-time voice agents on the underlying speech models rather than a full orchestration platform
- Pro: Sonic (text-to-speech) and Ink (speech-to-text) models are ranked #1 on Artificial Analysis' Speech Arena and Speech-to-Text leaderboards
- Pro: Free plan includes a provisioned phone number and up to 8 concurrent voice-agent calls, enough to test a live agent before paying
- Pro: Telephony is billed transparently at $0.06/minute across every plan, not hidden behind custom pricing
- Con: Instant and professional voice cloning, plus a commercial-use license, require the paid Pro plan and above
- Con: Only 2 concurrent text-to-speech requests on the Free plan, thin if you're generating several scripts in parallel
Cartesia's pricing structure appears fair, especially with a generous free tier offering 20K credits.
Watch out
Prepaid agent usage can lead to overage if not monitored.
- Starting price
- Free plan
- Free plan
- Yes
Best for: Engineering teams who want to self-host, audit the full stack, or embed voice AI directly into their product
- Pro: Core framework is open source and free, enabling full code-level customization and self-hosting
- Pro: Enterprise-grade hosted API available for teams that want managed infrastructure without giving up flexibility
- Pro: Designed from the start for embedding in products rather than operating as a standalone platform
- Con: Requires more engineering effort to stand up than hosted platforms like Retell or Phonely
- Con: Smaller community and less third-party integration documentation than Vapi
Vocode's pricing is generous for individual developers and startups, offering a robust 'Vocode Core' for free.
Phonely
No-code AI phone answering platform designed to be live for a small business in under an hour
- Starting price
- From $50/mo
- Free plan
- Yes
Best for: Small and mid-size businesses that need a 24/7 AI receptionist without developer resources
- Pro: No-code dashboard lets non-technical users configure agents, conversation flows, and integrations without code
- Pro: Handles inbound appointment booking, CRM updates, and payment processing out of the box
- Pro: Raised $16M Series A in April 2026, indicating commercial traction and continued platform investment
- Con: Customization ceiling is lower than developer platforms; complex branching logic or custom LLM choices require workarounds
- Con: Younger platform with less production track record at enterprise scale compared with Vapi or Retell
This pricing structure is best for small to medium businesses looking for a scalable AI voice agent solution, with larger enterprises benefiting most from the custom Enterprise plan.
Watch out
Annual billing overage rates are higher than monthly
Other AI Voice Agents tools worth considering
More published tools from our AI Voice Agents category, ordered by our category ranking. They are not part of the editorial picks above.
What Is an AI Voice Agent?
An AI voice agent is a software system that conducts phone or voice conversations autonomously, without a live human agent. It combines three components: a speech-to-text layer that transcribes the caller in real time, a language model that decides what to say and what actions to take, and a text-to-speech layer that speaks the response.
The platforms in this guide sit above those components and handle the orchestration:
- Telephony integration (SIP trunks, Twilio, direct phone numbers)
- Turn-taking and interrupt detection (so the agent does not talk over the caller)
- Tool calling (the agent can book an appointment, look up an account, or transfer a call mid-conversation)
- Analytics and call logs for monitoring and improvement
They differ sharply on who they are built for:
- Developer-first platforms (Vapi, Vocode, Cartesia) expose raw APIs and let you wire in any LLM or TTS provider
- Mid-tier platforms (Retell AI, Bland AI) add a visual builder and pre-built templates on top of an API
- Business-focused platforms (Phonely, ElevenLabs Agents) offer a no-code dashboard first
Why AI Voice Agents Matter in 2026
Businesses that handle high call volumes face a hard economics problem: human agents cost $25 to $50 per hour and cannot scale instantly. AI voice agents now handle routine calls, including appointment booking, FAQ responses, and lead qualification, at a fraction of that cost and at any concurrency.
The technology crossed a practical threshold in 2025. Latency on leading platforms dropped below 800 milliseconds end-to-end, voice naturalness improved enough that a significant share of callers cannot distinguish the agent from a human on a first call, and telephony integrations became reliable enough for production use. The gap between a polished demo and a production deployment is still real, but it is much smaller than it was two years ago.
Key Features to Look For
End-to-end latency (Essential)
The time from the caller finishing a sentence to the agent beginning its response. Under 800ms feels natural; over 1.2s creates friction. Measure this on real PSTN calls, not demos.
Interrupt and barge-in handling (Essential)
The agent must stop speaking and process the new input when a caller interrupts. Poor handling makes agents feel robotic and drives callers to hang up.
Telephony integration (Essential)
Native phone number provisioning, SIP trunk support, and inbound/outbound call management. Some platforms require you to bring your own Twilio account; others abstract it entirely.
Tool calling and actions (Important)
The ability to call external APIs during a call: looking up a customer record, booking a slot in a calendar, or transferring to a human agent. This is what separates an answering agent from a functional one.
Voice quality and cloning (Important)
The naturalness of the generated voice and the option to clone a specific voice for brand consistency. Quality varies widely across providers even at similar price points.
Analytics and call monitoring (Nice to have)
Transcripts, sentiment analysis, call recordings, and success-rate tracking. Essential for iterating on prompts and detecting failure modes in production.
How to Choose
-
Measure latency on a real call, not a browser demo. PSTN calls add jitter that browser WebRTC calls hide.
-
Add up the full per-minute cost: platform fee plus telephony plus LLM plus TTS. Headline rates rarely reflect what you actually pay.
-
Check whether the platform handles your call volume. Concurrent call limits and overage pricing matter at scale.
-
Test interrupt handling with a real caller who talks over the agent. This is where most demos fall apart.
-
Verify compliance requirements before committing: HIPAA BAA availability, data retention policies, and call recording consent tooling.
Evaluation Checklist
Place a real outbound call and measure time-to-first-word on a mobile connection, not a browser demo.
Interrupt the agent mid-sentence and check whether it stops cleanly, restarts correctly, and stays on task.
Request a full cost breakdown: platform per-minute plus telephony plus your chosen LLM plus TTS.
Confirm concurrent call capacity and what the overage cost looks like at 2x your peak volume.
Test tool calling with a realistic action (calendar lookup, CRM write) to verify it completes reliably mid-call.
Check data retention, call recording storage, and compliance documentation before using with customer data.
Pricing Overview
Free or developer
Prototyping, open-source self-hosting (Vocode), or small call volumes
$0 to $25/month
Usage-based (platform only)
Developer teams who manage their own LLM and telephony stack
around $0.05 to $0.09/min (platform layer alone)
All-in mid-market
Teams wanting bundled telephony, support, and a visual builder
$299 to $500/month base plus usage
Enterprise
High concurrency, compliance requirements (HIPAA), dedicated support
Custom, often $40k to $70k/year for large deployments
Mistakes to Avoid
- ×
Choosing a platform based on demo voice quality alone and discovering latency problems only in production.
- ×
Underestimating total per-minute cost by ignoring telephony and LLM layers until the first invoice.
- ×
Deploying without testing interrupt handling, which is the most common reason callers hang up on an AI agent.
- ×
Starting with a developer-first platform when the team lacks the engineering capacity to configure and maintain it.
- ×
Treating a single use case (outbound reminders) as proof the platform handles a different one (complex inbound support) equally well.
Expert Tips
- →
Run a latency benchmark on a real phone call before signing any contract. Ask the vendor for a trial with actual PSTN routing, not a web widget.
- →
Keep your initial agent scope narrow: one call type, one outcome. A well-tuned agent that reliably books appointments outperforms a broad agent that handles everything poorly.
- →
Monitor your call completion rate and hang-up timing. If callers consistently drop around the 30-second mark, your agent is failing on interrupt handling or the first response is too slow.
- →
For high-volume outbound, test your script on 50 to 100 real calls before scaling. LLM output variance that looks fine in testing surfaces at volume.
- →
Segment your call flows by intent before building. A single agent trying to handle billing disputes, appointment booking, and product questions will underperform three focused agents.
Red Flags to Watch For
-
A demo that only runs in a browser tab. PSTN latency is materially different and platforms that hide this may not be production-ready.
-
Headline per-minute rates that do not mention telephony and LLM costs separately. The real number is almost always 2 to 3 times higher.
-
No mention of interrupt handling or barge-in support in the documentation.
-
Compliance claims (HIPAA, SOC 2) without supporting documentation or an auditable BAA available on request.
-
No call logs, transcripts, or analytics. You cannot improve what you cannot see.
The Bottom Line
For engineering teams building custom voice AI infrastructure, Vapi offers the deepest provider flexibility, while Retell AI delivers comparable developer control with better out-of-the-box latency numbers and cleaner compliance documentation. Bland AI is the strongest option for high-volume outbound campaigns. ElevenLabs is the right choice when voice expressiveness is the top priority and the orchestration complexity is low. Phonely is the fastest path to a working AI receptionist for a small business with no technical staff. In every case, test on a real phone call before committing: the gap between a demo and a production call is where most voice agent projects run into trouble.
Frequently Asked Questions
What is the best AI voice agent in 2026?
It depends on your use case and team. Vapi is the top choice for developer teams who need full control over their LLM, TTS, and telephony stack. Retell AI is the best balance of developer depth and lower-code usability with strong latency figures. Phonely is the fastest option for a small business that needs a working AI phone agent without engineering resources. There is no single best platform; the right one depends on call volume, technical capacity, and how much customization your use case requires.
How much does an AI voice agent cost per minute?
Headline platform rates range from around $0.05 to $0.12 per minute, but these cover only the platform layer. You also pay for telephony (typically $0.01 to $0.02 per minute via Twilio or similar), the LLM you use, and the TTS provider. All-in production costs typically land between $0.10 and $0.30 per minute depending on model quality choices. Platforms like Phonely bundle more of these costs, simplifying budgeting at the expense of provider flexibility.
What is the difference between Vapi and Retell AI?
Both are developer-first platforms, but Vapi gives you more provider flexibility: you can swap in almost any LLM or TTS provider. Retell AI is more opinionated, which makes setup faster and its stated end-to-end latency (as low as 600ms) is a key differentiator. Retell also includes SOC 2 certification and HIPAA readiness as standard, whereas Vapi charges extra for a HIPAA BAA. Teams with strong provider preferences tend toward Vapi; teams that want reliability out of the box tend toward Retell.
Can AI voice agents handle interruptions from callers?
Yes, all the platforms in this guide support interrupt detection, but quality varies significantly. The best implementations stop the agent mid-sentence, discard the in-progress audio, process the new input immediately, and continue the conversation without confusion. The worst implementations either talk over the caller or produce awkward pauses. Testing barge-in handling on a real call is one of the most important evaluation steps before committing to a platform.
Are AI voice agents suitable for regulated industries like healthcare?
Some platforms are. Retell AI is SOC 2 certified and HIPAA-ready with SSO as standard features. Vapi offers a HIPAA BAA but charges an additional monthly fee for it. Cartesia supports cloud, on-premise, and on-device deployment for data-residency requirements. If you are building for healthcare, legal, or financial services, verify that the platform has a signed BAA available, documented data retention policies, and call recording consent tooling before deployment.
Cite this page: Toolradar, "Best AI Voice Agents in 2026", updated September 2026, https://toolradar.com/guides/best-ai-voice-agents
Sources
Prices and plan details on this page come from each vendor's own pricing page, re-checked by the Toolradar pricing tracker:
- Vapi pricing
- Retell AI pricing, checked
- Bland AI pricing, checked
- ElevenLabs pricing, checked
- Cartesia pricing, checked
- Vocode pricing, checked
- Phonely pricing, checked
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