AI voice agent platforms compared (2026)

An AI voice agent platform answers the phone for you: it listens, decides what the caller wants, calls your systems, and talks back, and it bills you by the minute. There are now dozens of them, and their pricing pages are written to make side-by-side comparison hard. This page compares the eight you are most likely to shortlist, by what each one runs for you and what a minute actually costs.

The short version: if you want one price that includes the models, look at Bland. If you want to pick every model yourself, look at Vapi or Retell. If you want to write the agent as code, use LiveKit Agents or Pipecat. If voice quality and response time decide whether your callers stay on the line, try Cartesia Managed Agents, which runs the speech models that rank first on independent leaderboards.

We build Cartesia, so weigh our view accordingly. Every competitor price below comes from that vendor’s own pricing page, read on October 3, 2026.

What a voice agent platform does

Every voice agent runs the same loop. Streaming speech-to-text transcribes the caller while they talk. A turn detector decides when they have finished. A language model plans the reply and calls tools, such as a calendar or an order lookup. Text-to-speech streams the answer back. Our guide to how voice agents work covers the loop in detail.

A platform hosts that loop and adds the parts nobody wants to build twice: phone numbers, call transfers, a configuration UI, call logs, and evaluations. A framework gives you the same loop as code you deploy yourself. The main choice is how much of the stack you want to own, more than which vendor you pick.

The platforms, one by one

Cartesia Managed Agents

Managed Agents combines Ink 2 for speech-to-text, an LLM you choose, and Sonic 3.6 for speech, according to the Managed Agents docs. Both speech models are our own. Ink 2 ranked first for word error rate on Artificial Analysis’s streaming leaderboard as of June 2026 and predicts the end of a turn itself, without a separate voice activity detector. Sonic 3.6 ranked first of 94 models on the Artificial Analysis Provider Voice Arena as of August 2026.

You configure an agent in the playground or through the API, and you can give it tools, a knowledge base, and a phone number. Calls cost $0.06 a minute on every plan, and a Cartesia-provided number adds $0.014 a minute. For a limited time, LLM usage is included for agents built in the playground (pricing). Concurrency runs from 8 calls on Free to 60 on Scale.

Pick it when the voice is the product: support lines, receptionists, and any call where a slow or robotic reply loses the caller. Check that your CRM or scheduling system has an integration; if not, the agent can reach it through a webhook tool.

Vapi

Vapi is a developer platform for composing an agent from parts you choose. Per Vapi’s pricing page, hosting costs $0.05 a minute and the models (transcriber, LLM, voice) pass through at cost, so the real rate depends on your choices. Vapi’s own estimate for 1,000 minutes lands at $82 to $129 a month, about $0.08 to $0.13 a minute. The free tier comes with $5 of credit and 4 concurrent calls. Vapi chose Cartesia as its default voice provider in 2024.

Pick it when you want control over every model and are comfortable reading three or four invoices’ worth of line items.

Retell AI

Retell sells a low-code platform aimed at call-center automation. Its pricing page lists $0.07 to $0.31 a minute on pay-as-you-go, with 20 concurrent calls included. The default estimate breaks down as $0.055 for Retell’s voice infrastructure, $0.04 for the LLM, and $0.015 for telephony, about $0.11 in total. Retell offers voices from several providers, including Cartesia, and reports 2 to 3 times faster time to first audio with Cartesia than with the next best provider on its platform.

Pick it when non-engineers will build and maintain the call flows.

Bland AI

Bland prices everything in one number. Bland’s pricing page lists $0.14 a minute on Start and $0.12 on Build ($299 a month platform fee), with the LLM, speech-to-text, and text-to-speech included and telephony billed separately. Enterprise plans add on-prem or VPC deployment and forward-deployed engineers.

Pick it when a predictable bill matters more than choosing the models.

Synthflow

Synthflow targets enterprise contact centers with a no-code builder, native telephony, and implementation support. Its pricing page quotes enterprise contracts starting at $30,000 a year, scoped by call volume, concurrency, and integrations.

Pick it when you want a vendor to run the rollout with you and have the budget for an annual contract.

ElevenLabs Agents

ElevenAgents bills by call minute: each plan includes a block of minutes, and extra minutes cost $0.08, or $0.16 when calls exceed your concurrency limit, per ElevenLabs’ agents pricing. The LLM is billed on top. Our ElevenLabs pricing breakdown walks through a 10,000-minute workload.

Pick it when your team already uses ElevenLabs for creative work and wants agents from the same account. For latency-sensitive calls, compare first: in Coval’s August 2026 measurements, Sonic 3.5 reached first audio in 351ms at P90, while every ElevenLabs model tested took more than a second.

LiveKit Agents

LiveKit is the open-source WebRTC infrastructure under many voice products, and LiveKit Agents is its framework for writing the agent loop in Python or Node. You can self-host it or deploy to LiveKit Cloud, which charges $0.01 per agent session minute after the included allowance, with inference for most popular models available through the same bill.

Pick it when you have engineers and want full control without running media servers yourself. LiveKit partners with Cartesia, and Sonic and Ink are available through its inference billing.

Pipecat

Pipecat is an open-source Python framework, started by Daily, for building voice and multimodal agents as a pipeline of services. It is free; you pay the model providers and host it wherever you like.

Pick it when you want the most control and the fewest platform opinions. Our Pipecat tutorial builds a working agent with Ink and Sonic and shows how eager turn detection cuts about half a second off each reply.

Side by side

Listed prices are a poor guide on their own. A “$0.05” platform with a premium voice and a large LLM can cost more than a “$0.14” bundle. Price the same call on every finalist: same LLM, same voice quality, same telephony.

How to choose

Four questions settle most decisions:

1. Who will maintain the agent? If it is an operations team, pick a platform with a visual builder (Retell, Synthflow, Bland, or Managed Agents). If it is engineers, Vapi, LiveKit, or Pipecat will feel less constraining.
2. How fast does the agent answer? People hand off turns in about 200 milliseconds, and a one-second pause reads as a dead line. Measure time from the caller’s last word to the agent’s first audio, at the 90th percentile, on a real phone line. Medians on clean audio hide the slow calls.
3. How does it handle the hard strings? Read a confirmation code, a street address, and a phone number to each finalist. Transcription errors on these are the ones that turn into wrong bookings.
4. What does your volume cost? Multiply your expected monthly minutes by the all-in rate, including the LLM and telephony, and check what happens when you exceed the plan’s concurrency.

Then run a pilot. Our AI call center guide has a pilot plan, and the AI receptionist guide covers the small-business case.

Try Cartesia Managed Agents

You can build and test-call an agent in the Cartesia playground on the free plan, which includes $1 of agent usage a month. If you’d rather keep your current platform, Vapi, Retell, LiveKit, and Pipecat all support Sonic as the agent’s voice.

Related guides

• AI voice agent: what it is and how to build one
• Voice AI companies to know in 2026
• Best speech to text models compared
• Managed Agents documentation