9 Best AI Voice Agent Platforms of 2026

Retell AI is the strongest option for operations teams running real contact center traffic. It goes beyond scripted calls with agentic warm transfers that brief the receiving human, agents that work through phone trees and enter extensions, persistent memory of each contact across calls and texts, and a mix of deterministic and generative responses so disclosures and identity checks follow exact wording. Pay as you go costs $0.07 to $0.31 per minute depending on the model and voice, starts with $10 in free credits and includes 20 concurrent calls, simulation testing, webhooks and API access. Retell publishes component prices, such as $0.055 per minute for its voice infrastructure and $0.015 per minute for its platform voices, so you can estimate costs line by line. HIPAA with a BAA, SSO, role-based access control and 24/7 support require the Enterprise plan, which is priced by sales.

Vapi ranks first for this audience because it treats a voice agent like any other piece of software you build: you pick the transcriber, the language model, the voice and the transport, and Vapi bills $0.05 per minute for hosting while passing model costs through with no markup. Every plan includes unlimited agents, critical monitoring and call testing and simulation, and you can start on usage-only billing with $5 in free credits. Vapi's own calculator shows a 1,000-minute month landing between $82 and $129 with Deepgram, OpenAI and ElevenLabs, which makes the stack cost easy to see. The limits show up as you grow. Usage-only accounts get 4 concurrent calls and 14 days of raw data retention, the Core package costs $29 a month for 10 concurrent calls and email support, and HIPAA-eligible handling is a $2,000 per month add-on. Teams that want a single all-in rate will find Bland AI or Telnyx simpler to budget.

ElevenLabs Agents puts the company's voice models behind a full agent builder, and it is the easiest way here to get a natural-sounding agent live on several channels. You configure voice, language, knowledge base, system prompt and workflows in one place, then deploy across phone, web, WhatsApp, SMS and email, and the agent keeps context across all of them. Guardrails, simulations and automated tests check behavior before customers reach it, and ElevenLabs says agents work in 90+ languages. Pricing is a subscription with included minutes: the free plan gives 15 minutes of calls, Starter costs $6 a month for 75 minutes and 6 concurrent calls, and Pro costs $99 a month for 1,238 minutes. Additional minutes cost $0.08 on every tier, with LLM and telephony billed at cost. The trade-off for larger operations is that BAAs for HIPAA, custom SSO and elevated concurrency need the Enterprise plan.

Telnyx is the pick for builders who want fewer vendors in the call path. It is a licensed carrier in 45+ countries, runs LLM inference on its own GPUs and bundles orchestration, speech-to-text and text-to-speech into a $0.05 per minute voice engine. LLM tokens are billed per token at Telnyx's GPU rates and telephony at carrier cost, starting at $0.0032 per minute for SIP inbound, and Telnyx estimates a production agent near $0.06 per minute. Pay as you go already includes 500 concurrent calls, 80+ languages and full-stack tracing with latency breakdowns, and A-level STIR/SHAKEN attestation helps eligible US outbound calls avoid spam labels. Two details matter when you model costs: the voice engine rounds each call to 60-second increments, so short calls cost more than the headline rate suggests, and support on pay as you go is community only until you commit to the $2,000 per month Growth plan.

Deepgram's Voice Agent API is the most infrastructure-like option on this list, and it suits engineering teams that want to own the application and leave the speech loop to a vendor. One WebSocket takes audio in and returns audio out, while Deepgram runs end-of-turn detection, barge-in, function calling and conversation state. You can bring your own LLM through an OpenAI-compatible endpoint or Bedrock with ordered fallback, use a third-party voice, and change the model or voice mid-conversation. Every turn returns a latency report split by speech-to-text, LLM, tool and text-to-speech time. Pricing is per minute of connection: $0.075 on pay as you go with a managed LLM included, as low as $0.050 when you bring your own model or voice, and $0.163 for the advanced model tier, with $200 in free credit to start. Teams with strict data rules can self-host on Kubernetes with a Helm chart. You still need your own call handling and phone numbers.

Bland AI takes the opposite approach to Vapi: instead of letting you pick vendors, it runs its own speech-to-text, language model and text-to-speech, and charges one rate that covers all three. The Start plan costs $0.14 per minute with no platform fee and no card required, and the Build plan lowers that to $0.12 per minute for $299 a month while raising limits to 50 concurrent calls and 2,000 calls a day. Telephony runs on your own Twilio account, any SIP trunk or Bland's built-in Twilio at pass-through cost. Bland targets healthcare, insurance and financial services, and lists SOC 2 Type I and Type II, HIPAA with a BAA, GDPR, ISO 27001 and FedRAMP 20x Class A. The trade-offs are tight Start limits of 10 concurrent calls and 100 calls a day, transfer time billed at $0.05 per minute, and on-prem or VPC deployment only on Enterprise.

PolyAI pairs self-serve plans with a developer platform that treats agents as code. With the agent development kit you edit flows, functions and voice configuration locally in any editor, keep every resource as a versioned file in Git, run automated test suites from the CLI and ship changes with the poly push command in your CI pipeline. Its Dialog-RSN-1 model is audio-native with under 300ms median first-token latency, and custom functions can call your backend during a call, for example to look up orders or trigger refunds. Plans start at $49 a month for 250 minutes and 5 calls at once, then 30 cents a minute, with Plus at $199 for 1,000 minutes and Scale at $299 per location. That makes PolyAI pricier per minute than usage-based platforms at volume, and HIPAA, SSO and an uptime SLA need Enterprise.

Cartesia is best known for its text-to-speech and speech-to-text models, and its Managed Agents product wraps those models into phone agents with low entry costs. The free plan includes $1 of prepaid agent usage a month, 1 Cartesia-provisioned number and 8 concurrent calls, and Pro costs $5 a month with $5 of prepaid agent usage, 3 numbers and 12 concurrent calls. Agent calls are billed at $0.03 per minute, which Cartesia shows as a cut from $0.06, plus $0.014 per minute on a Cartesia number and separately billed LLM usage. Agents take inbound calls and place outbound calls to lists of up to 5,000 numbers on Cartesia, Twilio or SIP numbers. You can call an agent from the browser and score the call with metrics you write, and every call keeps its recording and transcript. It has fewer contact center features, such as warm transfers and phone tree handling, than Retell AI or Vapi document.

Twilio ConversationRelay is less a voice agent platform than a building block, and it makes sense for teams whose numbers, call routing and contact center already run on Twilio. It handles the voice side, speech-to-text and text-to-speech with Deepgram Flux, automatic language detection and SSML, and streams text to and from your own LLM over a WebSocket API. You can build flows in the drag-and-drop Studio Widget or through the APIs, and hand callers to a live agent when the AI cannot resolve an issue. Twilio cites p50 latency of 491 ms in internal benchmarks. ConversationRelay costs $0.07 per minute on the US pricing page, and Twilio Voice charges apply on top, for example $0.0085 per minute to receive a local call and $1.15 a month for a local number. You write and host the agent logic yourself, with no built-in agent builder, simulated test calls or agent analytics.